Effect of Addition of Starch and Yam Flour on the Sensory and Instrumental Properties of Low Fat Sausages

This research evaluates the effect of the addition of yam flour and starches on the sensory and instrumental properties of low-fat sausages. A 3×5 factorial arrangement completely randomized was applied to sausages using the following factors: fatty mimetic (flour, native starch and pregelatinized starch) and fat substitution (0, 10, 20, 30 and 40%), evaluating their sensorial and instrumental properties with three replicates per treatment. By replacing 30 and 40% of the fat in the sausages, these were less bright and redder, while 10% of the fat replaced by native starch and pregelatinized, the values of luminosity increased (p≤0.05) with respect to the control treatment. By replacing 10 and 20% of fat with mimetics, an improvement in texture was observed, reducing the hardness between 10.23 and 25.86%. Sensory evaluation showed that this substitution did not cause any alteration in the acceptability of the sausages (p≤0.05) with respect to the control formulation, with the exception of those made with native starch at 20% substitution, which was less accepted in flavor. The substitution of 10 and 20% of fat for flour and pregelatinized starch are the most recommended in the production of sausages with better sensory acceptance, texture and luminosity.


INTRODUCTION
Sausages are widely accepted by consumers of all ages because of their excellent nutritional and sensory characteristics (Feng et al., 2013).One ingredient used in the formulation of these types of products that influences these characteristics is animal fat.This is used in proportions of 20 to 30% in traditional sausages around the world (Choe et al., 2013;Feng et al., 2013;Oliveira-Faria et al., 2015) and its main objective is to achieve the development of products with high technological and sensorial quality, but its consumption, due to the high contribution of Saturated Fatty Acids (SFA) (30 to 60 g/100 g), has been associated with the development of certain cardiovascular and chronic diseases such as obesity, cancer, hypertension and stroke (Zhang et al., 2010;Pacheco Perez et al., 2011;Rivera Ruiz, 2012), so consumers are interested in reducing dietary fat intake, focusing on the purchase of healthy products with high nutritional value added and sensorially acceptable (Pacheco Perez et al., 2011;Brewer, 2012;Feng et al., 2013).
As an alternative to reducing SFA, it has been suggested to partially replace animal fat with other ingredients that do not contribute calories or improve the fatty acid profile.Among the alternatives proposed, the substitution of part of the fat with water (Ahmed et al., 1990), vegetable oils (Salcedo-Sandoval et al., 2013;Cofrades et al., 2014), protein (Cengiz and Gokoglu, 2007;Yoo et al., 2007) and fiber (Campagnol et al., 2012;Tomaschunas et al., 2013), leading to healthier products, but some problems related to texture and sensory quality have been reported.In order to improve these properties, the use of carbohydrates as an excellent alternative due to their properties of water retention and gel formation has been indicated, which allows to be able to preserve certain organoleptic characteristics that can vary by the diminution of the fat, like the texture (Tokusoglu and Ünal, 2003;Mallika et al., 2009).
One of the most used industrial carbohydrates is starch, due to its economic benefits, high availability and wide applicability.Different studies show the potential of starches and flour rich in this polymer to be incorporated in low-fat meat products (Pietrasik and Janz, 2010;García et al., 2012;Feng et al., 2013;Bastos et al., 2014).For example, when using potato enzyme starch as a substitute for fat in sausages, no differences were observed in the texture profile and the Sensory properties with the control sample (Liu et al., 2008).When using modified cassava starches, there were no significant differences with the control sample regarding juiciness, oiliness, texture, taste and general acceptability up to 21 days of storage (Luo and Xu, 2011).When using flours in the elaboration of low-fat meat sausages, such as green banana in the shell, formulations with textural characteristics similar to the control have been found (Araya-Quesada et al., 2014).
Taking into account the wide applicability of starches due to the contribution of their technofunctional properties, they are subjected to modification processes, through physical, chemical, enzymatic or combined methods that enhance or provide an improvement in functionality, to resist the requirements of modern food processing, as well as to meet the demands of innovative and high quality food by the customer (Amani et al., 2005;Kaur et al., 2004).It has also been explored to obtain starches and flours from carbohydrate-rich tubers whose starches possess excellent techno-functional characteristics and ensure that products of excellent quality are obtained, as well as being able to diversify the sources of crops traditionally used to obtain these Such as maize, potato, wheat, rice and cassava, which are highly demanded in the food industry (Nguimbou et al., 2012;Torres Rapelo et al., 2013).
The starch obtained from yams has been reported as an alternative source to commercial starches because it has certain desirable techno-functional properties, among which is its great capacity to maintain its viscosity stable at high temperatures and low pH values (Alves et al., 2002), it has also been reported that it contains a low lipid content of less than 0.5% (Pacheco and Techeira, 2009).Similarly, it has been reported that the flour obtained from yams has low-fat content (between 0.37 and 0.45%) (Techeira et al., 2014) this characteristic that allows them to be used as a substitute for fat.
In this research, three modified starches were characterized in order to select among them the one that would present the best techno-functional properties to be used as a substitute for fat.Therefore, the aim of this study was to evaluate the effect of the addition of native starch, modified starch and yam flour on the sensory and instrumental properties of low-fat sausages, in order to obtain a product reduced in animal fat that can be accepted by the consumer.

Raw materials:
The plant material used in the research corresponds to the Dioscorea rotundata yam variety, supplied by local producers in the city of Sincelejo (Colombia).Beef and pork fat were obtained from a local supermarket in the city of Sincelejo (Colombia).The ingredients and additives used in the sausage manufacturing process were obtained from the input distributor TECNAS S.A.

Preparation of starches and yam flour:
The production of starches and yam flour was carried out at the Unitary Operations Plant of the University of Sucre.For the extraction of the Native Starch (NS) of yam, continuous bubble equipment was used at pilot scale, designed to obtain starch and recovery of its mucilage, followed the methodology proposed by Salcedo et al. (2014).
The Pregelatinized Starch (PS) of yam was performed in a batch reactor, following the method set forth by Barragán-Viloria et al. (2016) with some modifications.A continuous stirring system was used and heating at 81°C for 10 min at 300 rpm.0.5 mL of ethanol was added for each gram of starch while stirring for 1 h, then methanol, equivalent to one-third of the water in the suspension, was added with continuous stirring for 5 h.Finally, the samples were dried in a convective oven at 40°C for 24 h and ground until passing through a 100 mesh sieve.
Acetylated Starch (AS) was obtained following the method modified by Salcedo Mendoza et al. (2016a).For this a 4.5% starch slurry was prepared and stirred for 60 min at 30°C, 3.0 mL of acetic anhydride was added dropwise to the stirred suspension, maintaining the pH between 8.0-8.4 using 3.0 NaOH solution % (W/v).After completion of the reaction time, the suspension was adjusted to pH 4.5 with 0.4N HCl.The starch obtained was washed, dried in a convective oven at 40°C for 24 h and reduced in size until passed through a 100 mesh screen.
Enzymatic Starch (ES) was obtained by preparing an aqueous solution (120 mL) containing 20 g/L of starch and 315 μL of the hydrolyzing enzyme (commercial α-amylase).The solution was kept under stirring at a pH of 5.5 (0.1 mol/L citrate buffer).Reducing sugars were determined (Miller, 1959) to calculate the dextrose percent (DE).The reaction was stopped using hydrochloric acid (2 mol/L) to lower the pH to 1.5 over the course of 5 min and then using sodium hydroxide (2 mol/L) to raise the pH to 6. Finally, the Starch was allowed to settle, the supernatant was removed, dried in a convective oven at 40°C for 24ch, milled and the sample was passed through a 100 mesh screen.The enzymatic activity was determined following the method proposed by Matute et al. (2012).
The Flour (F) of yam was obtained following the method proposed by Pérez and Pacheco de Delahaye (2005), with some modifications.The tubers were washed with potable water to remove all soil and disinfected with a solution of 200 ppm of sodium hypochlorite for 10 min by immersion, then they were peeled, chopped and immersed in 0.1% citric acid solution and convectively dried 50°C for 12 h.Subsequently, they were subjected to a process of reduction of size up to 100 mesh.
Infrared spectroscopy with Fourier Transform (FT-IR): Infrared spectra of native starch pregelatinized starch and yam meal were obtained using a Fourier transform infrared spectrometer (Thermo scientific reference Nicolet iS5 Transmission iD1) in the region of 500 to 4000 cm -1 .The crystals were obtained by mixing 20 mg of starch with KBr in a ratio of 1: 5 (starch: KBr) and collecting thirty-two readings at a resolution of 4 cm -1 (Colussi et al., 2015).
Water Absorption Index (WAI), Water Solubility Index (WSI) and Swelling Power (SP): The method modified by Salcedo Mendoza et al. (2016b).For this process, 1 g of starch was deposited on a dry basis in a previously tared centrifuge tube.To this tube, 25 mL of distilled water was added, preheated to the evaluated temperatures (60, 70 and 80°C).The suspension was placed in a water bath according to the temperature under evaluation for 30 min and was shaken manually at 10 min of heating initiation.It was then centrifuged at 565 g for 15 min.The supernatant (soluble starch) was then extracted and the total volume determined.Subsequently, a 10 mL sample of the supernatant was deposited in a pre-weighed Petri dish and dried in an oven at 70°C for 16 h.The weight of the Petri dish was recorded with the soluble material and the centrifuge tube containing the gel (insoluble starch).The values of WAI, WSI and SP were estimated from Eq. ( 1), (2) and (3): Sausages formulation and processing: For the formulation of the sausages, among the modified starches the one that presented the highest values of WAI, SP and WSI at 60 and 70°C was selected, following the formula proposed by Paternina et al. (2016) with some modifications based on the Colombian Technical Norm of meat products (NTC 1325(NTC , 2008)).Five formulations were made from five fatty substitutions by fatty mimetics (flour, native starch and modified starch) in a weight/weight ratio.The fat content replaced in the formulations, in percentages was 0, 10, 20, 30 and 40%, corresponding to 0, 2, 4, 6 and 8 g/100 g as shown in Table 1.To establish the level of fat to be replaced in the meat product, the fat content of commercial sausages was determined which included in  its formula pig fat and the maximum value to be replaced by fat was determined by finding hardness values statistically equal to the control formulation.
Meat emulsions were made from beef with a temperature of 4°C and a pH range of 5.8 to 6.4.Organoleptic characteristics such as color, odor and texture were evaluated on the obtained meat.Subsequently, the meat was cleaned by removing surface fat and connective tissue, then the fat and the meat were chopped forming cubes of approximately 5 cm in size, which were cured using curing salt (6% nitral).Subsequently, the chopped and cured meat and fat were put through to a fine grinding process, using a No. 22 JAVAR brand mill.The mixture of meat and additives was made in a JAVAR cutter with capacity for 5 L, the ingredients were added according to the following order: meat, ice, phosphate, erythorbate, condiments, spices, ice, fat, ice and fatty mimetic.After obtaining the emulsion, the different blends were filled into synthetic gut (19 gauge) using a FELSINEA stuffer, 12 cm portions were obtained and then scalded by immersion at 72°C for 30 min until the internal temperature of the product was reached (70°C), the samples were then cooled to room temperature and vacuum packaged, encoded and stored under refrigeration at 4°C.

Instrumental color measurement:
Color analysis was carried out by determining the color coordinates of the CIELAB space (L*: brightness or clarity; a*: green red coordinate and b*: yellow-blue coordinate) and the illuminant D65 was used as a reference system.The measurements were made on a Colorflex EZ 45 colorimeter (HunterLab®), following the methodology used by Grigelmo-Miguel et al. (1999).The colorimeter was calibrated with a standard white plate (L* = 97.83;a* = -0.43 and b* = 1.98) before each series of measurements.

Instrumental measurement of sausage texture profile:
A TX-T plus texturometer was used to determine the texture profile.For this, sausage samples with a length of 1.7 cm were used, which were placed horizontally and a 30% uniaxial compression was performed at a speed of 1 mm/s.A force of compression of 5 g was applied twice in succession on the samples, in order to simulate human chewing, where the force/time curve was obtained and the following parameters were calculated: hardness, cohesivity, adhesiveness, elasticity and chewability (Paternina et al., 2016).

Sensory evaluation:
The acceptability of each one of the formulations was evaluated using a non-trained sensory panel composed of 50 habitual consumer sausage starters, which were verbally recruited.The sausages used were cut into 8 g slices, served at room temperature in white dishes coded with three-digit numbers at random; The tasters were asked to evaluate the appearance, color, smell, taste and texture, using a mixed structured hedonic scale of 9 points where one (1) is "extremely disagreeable and nine (9) Determined the intention to buy, using a 5-point scale, where one (1) means "I certainly would not buy" and five (5) means "I would certainly buy." The sensory panel was performed in four sessions.On the first, the tasters were asked to evaluate the acceptability of the four samples formulated with the flour, on the second session, the ones that were made with the native starch, on the third session, they tasted those made with the pregelatinized starch and in the fourth session, the tasters evaluated the formulations that had the greater acceptance of the previous sessions.A control sample was included in each session.

Statistical analysis:
A categorical multifactorial design was used for the statistical analysis of the technofunctional properties of the starches and the instrumental results of color and texture.The sample was taken as factors for the techno-functional properties in five levels (NS, PS, AS, ES and S) and the temperature in three levels (60, 70 and 80°C).In the instrumental properties of the sausages the Fatty Mimic (FM) in three levels (S, NS and PS) and the replacement of fat in five levels (0, 10, 20, 30 and 40%).The selection of the most accepted sausages was carried out through a sensorial analysis, through an experiment to a classification route, with a completely randomized block design, where the factor of study was the substitution of fat in five levels (0, 10, 20, 30 and 40%) for each type of fatty mimetic (flour, native starch and pregelatinized starch to determine any effect of the independent variables on the dependent variables, an Analysis of Variance (ANOVA) (α = 0.05) was applied.To compare the obtained results a test of multiple ranges of comparison of means of Tukey was used.In all cases, three replications were performed for each treatment and the data were analyzed using the statistical package R 3.2.1 free version.

Water absorption Index (WAI), Water Solubility Index (WSI) and Swelling Power (SP):
The interaction of the temperature and sample factors generated statistically significant changes (p≤0.05) in WAI, SP and WSI of starches and flour.Table 2 shows the values obtained from WAI, SP and WSI, observing that as the temperature gradually increases, there is also a gradual increase in these properties.These increases may be due to the progressive relaxation of the forces of intragranular bonds with the increase of temperature, thus facilitating the entry of the water molecules into the granule, causing an increase in size and therefore a greater swelling power (Techeira, 2008).This same behavior was reported by Chen et al. (2017) and Huang et al. (2016) in native and modified yam flour and starches.
On the other hand, significant differences (p≤0.05) between samples were evidenced for each temperature evaluated in the WAI, SP and WSI values.The greatest increase in WAI and SP at different temperatures was obtained with the PS, possibly due to the disorganization in the granule structure, presence of weaker intragranular forces and loss of crystallinity with the consequent decrease of the pastification temperature, which allows it to absorb large amounts of water, causing swelling and increasing its volume at lower temperatures (Hernández-Medina et al., 2008;Techeira, 2008).This behavior is characteristic of this type of sample as a consequence of the nature of the process to which it has been put through, since the thermal treatments used in the preparation of pregelatinized starches cause strong changes in the crystalline structure mainly at the level of the amorphous regions, generating a rupture of its intragranular forces, which leads to the beginning of the unfolding of the double-helix regions, causing a disorganization in the granule structure (González and Pérez, 2003;Rincón et al., 2007).
The values of WAI and SP at 60°C of flour and starches: native and enzymatic are within the range reported by Salcedo Mendoza et al. (2016b) for native and acetylated cassava and yam starches (1,862 at 5,219 g/g for WAI and 1,877 at 5.38 g/g for SP), while those from PS are superior.In addition, SP values of the PS at different temperatures are within the range reported by Huang et al. (2016) in native and modified starches by enzymatic hydrolysis and a crosslinked carboxymethylated dual of Dioscorea opposita (4.74 g/g to 13.58 g/g) for temperatures between 65 and 95°C.
Taking into account that the PS has the capacity to absorb more water at temperatures of 60 and 70°C, it would be the most favorable starch for the development of low in fat meat emulsions, since it would allow, during the scalding of the products, to achieve The swelling and the absorption of water in sequence with the thermal changes and release of water by the proteins of the meat, favoring the texture of the products (Pietrasik and Janz, 2010).It is worth noting that WAI and SP of PS, the values are higher than those reported for native cassava starch (3.540 g/g for WAI and 3.387 g/g for SP) at 60°C (Salcedo Mendoza et al., 2016b).Of the flour, these values are not far off.Taking into account that cassava starch has great acceptance in the meat industry by favoring water retention, improving texture, wettability and imparting binding characteristics during the cooking process (Torres, 2012), it could be expected that when using flour And the PS of yam in meat products, these confer good water retention and desirable textural properties in the meat emulsions therefore the PS was selected among those modified for use with FM.
Instrumental color measurement: On Table 3, the values obtained from the chromaticity L*, a* and b* are shown.The interaction between the FM factors and the fat substitution used in the preparation of the emulsions generated statistically significant changes (p≤0.05) in the parameters L* and a*, but not in b*.In the luminosity, significant differences (p≤0.05) were found between the fat substitution percentages for each FM, obtaining the lowest values when replacing 30 and 40% fat.However, by replacing 10 and 20% of fat by NS and 10% by PS, the luminosity values increased in comparison to the control treatment, this was possibly influenced by the color of the starch gels.On the other hand, the lower values of luminosity detected in these formulations could be due to their lower fat content, since a reduction in fat level generally favors the appearance of darker colors (higher red values and values of), resulting from a reduction in the overall dispersion of light associated with fat dispersing properties (Pietrasik and Janz, 2010).A decrease in brightness was also evidenced in hamburger meat where green banana and oatmeal meal were used as fat substitutes (Bastos et al., 2014) and in chicken emulsions where green banana flour with peel was evaluated as a substitute for (Araya-Quesada et al., 2014), while using pigskin and amorphous cellulose as a fat substitute in meat products has shown an increase in brightness with respect to control (Oliveira-Faria et al., 2015).
The positive values of a*indicated a relative visual position towards the red color.Significant differences (p≤0.05) were found between the substitutions for each FM, noting that, when replacing the fat with the fatty mimetics said color increased in relation to the control formulation, becoming redder, as the percentage of substitution of fat increased, except for those formulated with a 10% replacement fat per flour.Possibly the significant increase in redness values with the decrease in fat content is due to the higher exposure of the lean meat content (Crehan et al., 2000).A similar behavior was evidenced in chicken emulsions when replacing fat with green banana flour (Araya-Quesada et al., 2014), in hamburger meat when using green banana and oatmeal as fat substitutes (Bastos et al., 2014) and in fat-substituted sausages with rice starch and mixtures of starch with gum (Feng et al., 2013).

. A similar behavior was
Instrumental measurement of sausage texture profile: On Table 4, the results obtained from the texture profile are shown.There were statistically significant differences (p≤0.05) between the interaction of the factors under study for the parameters hardness, elasticity, cohesiveness and chewing, but not in the adhesiveness.As for the hardness, the results showed that when replacing 10 and 20% the fat per yam flour, hardness decreases in 11.89 and 10.23%, respectively, when compared with the control formulation; Similarly, by replacing it by PS in the same percentages, the hardness decreased by 24.46 and 10.77%, respectively and by replacing it by 10% by NS, it decreased by 25.86%, while by replacing 40% fat by NS Increased by 17.98% and by PS by 30 and 40% increased by 12.77 and 10.86%, respectively; since the decrease of the fat content in meat products affects the hardness, because the fat contributes succulence, juiciness and tenderness, in such a way that foods with low content of fat present a greater hardness (Brewer, 2012).A similar behavior was observed when preparing low-fat chicken meat emulsions with ratios of 22.5/2, 20/4 and 17.4/6% fat/banana flour, where the addition of 17.4/6% fat/flour increased the hardness of products with respect to control and to 22.5/2% decreased (Araya-Quesada et al., 2014).Also, by increasing the addition of 3 to 6% inulin fiber gel in a low-fat emulsion paste the hardness increased by 25.30% (Álvarez and Barbut, 2013).On the other hand, the use of other fatty mimetics in meat products such as the combination of pork skin with amorphous cellulose (Oliveira-Faria et al., 2015) and wheat fiber (Choe et al., 2013) have increased the hardness of the products Between 3.84-51.31%and 25.06-64.86%,respectively, when compared to the control without fat replacement.
On the other hand, on the 30 and 40% substitutions the starches tended to generate a higher hardness than the flour, which may be related to the starch content, since this favors the formation of stronger structures, due to the swelling of the starches.Heat-starch granules embedded within the protein gel matrix (Carballo et al., 1995).This behavior was also evidenced by Pietrasik and Janz (2010) in a low-fat sausage type bologna, where the addition of pea starch generated a higher hardness than pea flour.
For masticability significant differences (p≤0.05) between each FM substitutions were found, noting that by replacing 10% fat for the mimetic, the chewiness of the sausages decreased in relation to the control formulation, whereas by substituting 40% by NS and 30 and 40% by PS, it increased.Also, there were significant differences (p≤0.05) between FM for each substitution evaluated except for the control.Starches tended to increase its chewiness when compared with flour, generating NS in substitutions 20 and 40% higher values and 30% on the PS, possibly because starches significantly influence the chewing ability and disintegration of the formulated gels (Araya-Quesada et al., 2014), noting that this feature intervenes directly in the fat content of food, as this improves mouthfeel and facilitates when chewing them (Totosaus and Pérez-Chabela, 2009).
The main effect of the factors under study was not significant (p≥0.05) on the adhesiveness of the sausages.These results are consistent with those reported by Araya-Quesada et al. (2014) in low-fat chicken meat emulsions.
Sensory evaluation: Fifty habitual consumers of sausages, evaluated the level of acceptance of low-fat sausages and control formulation (20% fat and 0% FM) according to the attributes of appearance, color, smell, taste and texture, also evaluated the intention of purchase, finding significant statistical differences (p≤0.05) for attributes of appearance, color, smell, taste and purchase intention when replacing fat with flour and NS, while replacing it with PS revealed significant statistical differences (p≤0.05) for attributes of appearance, taste, texture and purchase intention.
Table 5 shows the results of the sensory evaluation made by the tasters of the different sausages, using fat mimetics flour, NS and PS and the control formulation (20% fat and 0% flour).When replacing the fat with flour, it was observed that these in any of the evaluated parameters detected significant differences (p≥0.05) between the control sausage and the low-fat ones, although pig fat contributes significantly to the development of the flavor, The flavor profile, the appearance, the color and the texture of the sausage products (Tokusoglu and Ünal, 2003;Weiss et al., 2010;Gómez and Lorenzo, 2013).Similar results were evidenced by Pietrasik and Janz (2010) when comparing the acceptability judgments of the tasters of a low-fat bologna-type sausage with wheat flour, using the formulation 10% fat and 4% wheat flour and the control sample made with 22% fat.
However, among the sausages with different fat substitutions per flour, significant statistical differences were detected (p≤0.05).Regarding appearance, 84% of the tasters had a positive acceptance of the sausage with 40% of fat substitution, denoting a 50% between the "I slightly like it" and "I like it moderately" hedonic terms and was statistically equal to the control sausage already substituted with 30% of fat, rated by consumers with 62 and 54% respectively, among the same hedonic terms.The lowest acceptance of sausages for this attribute were those made with substitutions of 10 and 20%, rated by 30 and 34%, respectively, of the tasters in the term "I like it slightly", resulting statistically different (p≤0.05) to the sausage made with 40% of fat replacement.
As for the color attribute, 82% of consumers had a positive acceptance of the sausage made with 40% of fat substitution per flour, qualifying it 62% between the hedonic terms "I slightly like it" and "I like it moderately", being statistically equal (p≥0.05) to the control sausage and those formulated with substitutions of 20 and 30%, rated by consumers with 72, 48 and 58% respectively, among the same hedonic terms "I slightly like it" and "I like it moderately" and was statistically different (p≤0.05), to the sausage elaborated with 10% fat replacement qualified by the tasters with 60% between the hedonic terms "I'm Indifferent" and "I slightly like it", the latter being the one with less acceptance.
As for the smell, the sausages formulated with substitutions of 30 and 40% of fat per flour obtained the highest averages, being rated by the consumers between the hedonic terms "I slightly like it" and "I like it moderately", with percentages of 58 and 36% respectively, however the scent perceived by the tasters on these was statistically equal (p≥0.05) to that of the control sausage denoted with 64% between the hedonic terms "I slightly like it" and "I like it moderately" and the one made with 10% of fat replacement, rated 50% between the "I'm Indifferent" and "I slightly like it" hedonic terms, but they were different (p≤0.05)than the sausage made with 20% of fat substitution, obtaining the latter the lowest acceptance by the consumers, who denoted it with 44% between the hedonic terms "I'm Indifferent" and "I slightly like it".
As for the appearance attribute, the flavor perceived by the tasters of the sausage made with 40% of the substitution of fat by flour was statistically equal (p≥0.05) to the control sausage and the formulation with 30% of fat substitution, but different from sausages made with 10 and 20% substitutions, the latter being the least accepted, the consumers denominated them in the terms of "I'm Indifferent" and "I slightly like it" with ratings of 40 and 36% respectively.However, control sausages and manufactures with 30% and 40% of fat substitutions were rated by consumers among the hedonic terms "I slightly like it" and "I like it moderately" with percentages of 42, 46 and 42% respectively.
The tasters revealed that there were no significant statistical differences (p≥0.05) between the samples in terms of their texture, locating them according to the hedonic scale used, between the terms "I'm Indifferent" and "I like it moderately".Opposite results were reported by Bastos et al. (2014) who, when evaluating oatmeal and banana meal as fat substitutes in hamburgers, found that the tasters perceived differences in texture being more accepted those made with oatmeal, followed by that of banana and control.
Regarding the purchase intention, 70% of consumers stated their interest in acquiring the sausage made with 40% of substitution of fat per flour versus 10% of disinterest, being denoted by the term "I would probably buy it" The control sausage and the 30% fat substitution sausage were rated between the terms "I have doubts about whether I would buy it" and "I would probably buy it" and those with 10 and 20% fat substitutions were denoted in the term "I have doubts if I would buy it" 32 and 22% respectively.
In the results (Table 5) of the sensory evaluation emitted by the consumers of the different sausages using as yam FM, NS and the control formulation (20% fat and 0% NS), it was observed that the tasters perceived similar appearance and texture in the sausages where the fat was replaced by the NS with respect to the control.On the other hand, it was found that when substituting fat 30% for NS the sausages had a greater acceptance for the attributes of color and odor with respect to the control formulation and when replacing 20% the fat for NS they were less accepted as for the flavor that control, while with the other formulations the color, smell and perceived taste was similar to the control.Similar results were evidenced by Pietrasik and Janz (2010) when comparing the acceptability judgments issued by the tasters of a lowfat bologna-type sausage with native pea starch, using the formulation 10% fat and 4% starch with respect to the control sample, made with 22% of fat, where the consumers did not perceive differences in the appearance, the texture and the flavor between them.
However, the sausages made with 10 and 30% of fat replacement by NS were distinguished from the other formulations for the appearance attribute when obtaining the highest means, being statistically different (p≤0.05) to the sausage made with a replacement of 20 % and equal to the control and the one made with a substitution of 40%, where the sausages processed with substitutions 0 (control), 10, 30 and 40% were rated by consumers with 52%, 56%, 42% and 50%, respectively, between the hedonic terms "I slightly like it" and "I like it moderately", while the one made with a 20% replacement was denoted by 56% between "I'm Indifferent" and "I slightly like it".
As for color and smell, with a 30% substitution of fat by NS, the sausages had a positive acceptance of 82 and 78%, respectively by the consumers, who denoted it for color in 52% between the terms Hedonic "I slightly like it" and "I like it moderately", being statistically equal (p≥0.05) to the sausage made with 10% fat substitution, rated 42% among the same hedonic terms and was statistically different (p ≤ 0.05) to the other treatments.
I regard of the smell attribute, by replacing 10 and 30% of fat by NS the tasters define the sausages between the hedonic terms "I slightly like it" and "I like it moderately" with 56% and 46% of acceptability respectively and with the samples that have a 40% of fat replacement they define the samples between the terms "I'm Indifferent" and "I slightly like it" with a 60% of acceptability, among which the tasters did not reveal significant statistical differences (p≥0.05)among themselves, but between the ones that were elaborated with 30% of fat substitution in relation to the Control sample and the one produced with a replacement of 20%, were defined between the terms "I'm Indifferent" and "I slightly like it" with 56% and 44% of acceptability, respectively.
For the flavor, 86% of the consumers had a positive acceptance of the sausage where 10% fat was replaced by NS, qualifying it 32% in the hedonic term "I like moderately", being statistically equal (p≥0.05) to the control sausage already formulated with 30% replacement, denoted by the tasters between the hedonic terms "I like it slightly" and "I like moderately" with 30 and 36%, of acceptability, respectively and was statistically different (p≤0.05), to the sausages made with substitutions of 20 and 40%.When substituting 20% the fat for NS the sausage was less accepted, with a disinterest on the part of the tasters of 38%, who referred it (30%) between the hedonic terms "Indifferent" and "I like it slightly", however, was statistically equal (p≥0.05) to that produced with 40% fat replacement by NS (40%) referred to between the terms "I like it slightly" and "I like it moderately".
The tasters revealed that there are no significant statistical differences (p≥0.05) between the samples in terms of their texture, locating them according to the hedonic scale used between the terms "I'm Indifferent" and "I like it moderately".
Regarding the purchase intention, by replacing 10 and 30% of fat by NS, 70% of consumers stated their interest in acquiring the sausages being denoted by the term "I would probably buy it", for the other formulations they expressed the term "I have doubts if I would buy it", being the one made with a substitution of 20% of the fat that presented the most disinterest (32%).
In the results (Table 5) of the sensorial evaluation emitted by the consumers of the different sausages using as FM PS of yam, it was observed that the tasters did not detect significant differences (p≥0.05) in the attributes of color, smell, flavor and Texture between the control sausage and the low-fat sausages, while in the appearance itself, the sausages elaborated with substitutions of 10, 20 and 30% being more conspicuous in appearance than the control, being denoted by the tasters between the terms "I slightly like it" and "I like it moderately" with percentages of acceptance of 56, 58 and 36%, respectively, while the control was rated at 38% between the terms "I'm Indifferent" and "I slightly like it" and was equal to the one formulated with 40% of fat replacement accepted by 42% between the terms "I slightly like it" and "I like it moderately".
For the color and smell attributes, the tasters revealed that there are no significant statistical differences (p≥0.05) between the samples according to the hedonic scale used the terms "I'm Indifferent" and "I like it moderately".
In terms of taste, replacing 10% and 20% of fat by PS the sausages had greater acceptance according to the hedonic scale used between the hedonic terms "I slightly like it" and "I like it moderately", with percentages of acceptance of 48% for both formulations, this results were statistically different (p≤0.05)than those made with substitutions of 30 and 40% of fat denoted between the "I'm Indifferent" and "I slightly like it" hedonic terms with percentages of acceptance of 36% for both and all formulations were the same to the control sample denoted with a response of 26% with the hedonic term "I slightly like it".
For texture, by replacing fat by 20% by PS, 60% of consumers had a positive acceptance of the sausage, rating it 16% in the hedonic term "I like it slightly" and 30% in the term "I like it a lot ", being statistically equal (p≥0.05) to the control sausage and those formulated with substitutions of 10 and 30% of fat replacement, denoted by the tasters between the hedonic terms "I'm Indifferent "and" I like it slightly" with 34, 40 and 42% respectively and was statistically different (p≤0.05) to the sausage made with 40% of fat replacement by PS, obtaining the lowest acceptance with a disinterest by the tasters of 36%, who referred it (40%) Between the hedonic terms "I'm Indifferent" and "I like it slightly".Similar results were reported by Luo and Xu (2011), were a trained panel did not detect differences in taste and texture of the sausages were fat was replaced by modified cassava starches with respect to the control, observing higher but not significant scores, in the sausages of greater fatty content.
Regarding the intention to purchase, consumers stated their interest in purchasing sausages made with 10 and 20% fat substitutions per PS, being denoted by the term "I would probably buy it", for the other formulations, the tasters expressed the term "I have doubted if it would buy it", being the control sample the one that presented the most disinterest (36%) on the part of the tasters.
Table 6 shows the results of the sensory evaluation issued by fifty habitual sausage tasters, on the most widely accepted formulations using the different fatty mimetics, observing that consumers did not perceive statistical differences (p≥0.05) between the samples in terms of appearance, color, smell, taste and texture, placing them according to the hedonic scale used the terms "I like it slightly" and "I like moderately".Highlighting the positive acceptance they had of each parameter evaluated with ranges between 82-94%, 82-86%, 66-76%, 74-80% and 66-70% for appearance, color, smell, taste and texture, respectively, standing out the appearance, the color and the flavor with ranges greater than 70%, considered satisfactory results to be accepted by the consumers (Peuckert et al., 2010).
On the other hand, for the purchase intention, when substituting the fat 20% for PS and 40% for flour, there were no statistical differences (p≥0.05) between them, being located by the consumers in the hedonic term "Probably would buy" and by replacing 30% fat with NS, they expressed the term "I have doubts if i would buy".

CONCLUSION
The PS of yam was characterized by its high capacity to absorb water and its great swelling power desired characteristics in an FM.The flour and the PS of yam can be used in the production of sausages to replace the dorsal pig fat up to 20%, as it improves the texture of the products decreasing hardness and chewing and improves the color; Sensorially they do not present differences in the attributes of appearance, color, smell, flavor and texture with respect to the control formulation.

Fig. 1 :
Fig. 1: Infrared spectroscopy with Fourier Transform (FT-IR) of starches and yam flour observed byBastos et al. (2014) when comparing the different flours used as fat mimetics on the production of hamburgers.On the other hand, the main effect of the factors was significant (p≤0.05) on the blue-yellow chromaticity (b*).The positive values of b* indicated a tendency toward yellow.The highest values of b* were obtained by replacing 10% of the fat by the mimetics and the smaller ones by replacing it by 40%.These results agree with those reported by Araya-Quesada et al. (2014), Bastos et al. (2014) and

Table 1 :
Formulation of sausages with different percentages of fat substitution

Table 2 :
Techno-functional properties of starches and yam flour Promedium of three replicates±standard deviation; 2 Means with different letters in rows (lower case, temperature comparison) and columns (upper case, sample comparison) indicate significant differences (p≤0.05),according to the Tukey test.

Table 3 :
Average1 values of the color of the sausages Promedium of three replicates±standard deviation; 2 Control: 0% fat replacement; 3 Means with different letters in rows (Lower case letters, comparison between substitution and columns (Capital letters, comparison between FM) indicate significant differences (p≤0.05),according to the Tukey test; 4 NS: Not Significant the NS, AS and ES were within the range reported by Salcedo Mendoza et al.

Table 4 :
Average values1 of the texture profile of the sausages Promedium of three replicates±standard deviation; 2 Control: 0% fat replacement; 3 Means with different letters in rows (Lower case letters, comparison between substitution and columns (Capital letters, comparison between FM) indicate significant differences (p≤0.05),according to the Tukey test; 4 NS: Not Significant

Table 5 :
Average results of the acceptance test of sausages formulated with fatty mimetics

Table 6 :
Average results of acceptance test the most preferred sausages Means with different letters in columns indicate significant differences (p≤0.05),according to the Tukey test