Study Technological Factors Effect on the Loss of Protein , Carbohydrate and Lipid inside Royal Jelly in the Freeze Drying Process

This study published the mathematical models that were built by experiment to describe relationships between the loss of nutritional substances such as protein, carbohydrate and lipid of Royal jelly with technological factors in the freeze drying process such as temperature and pressure of freeze drying chamber; time of freeze drying process. These relationships were applied to determine the optimal technological factors. The results were found out the optimal technological mode as follow: the optimal temperature of freeze drying chamber was 24.35°C, the optimal pressure of freeze drying chamber was 0.368 mmHg and the optimal time of the freeze drying process was 19.225 h. Corresponding to these factors, the minimum value of the loss of protein, carbohydrate and lipid of Royal jelly were 1.968, 1.839 and 1.799% and the residual water content of final product after freeze drying were 3.51 under 4.5%. These optimal factors were really essential to establish the technological mode of the freeze drying process Royal jelly for preservation.


INTRODUCTION
According to overview of some research results about nutritional substances of Royal jelly such as Lercker et al. (1986); Schmidt and Buchmann (1992); Hattori et al. (2007); Sabatini et al. (2009), it is obvious that the Royal jelly is not only rich in essential nutrients such as protein, carbohydrate and lipid but also rich in bioactive compounds (10-hydroxy-2-decenoic acid (10-HDA) and its isomer) and vitamins B 1 , B 2 , B 3 , B 5 , PP, B c , H, A, D and E, … etc (Schmidt and Buchmann, 1992;Lercker et al., 1992;Hattori et al., 2007).In addition, the Royal jelly contains some minerals such as K, Ca, Na, Zn, Fe, Cu and Mn, with a strong prevalence of potassium (Stocker et al., 2005).
Protein of Royal jelly contains 29 amino acids, derivatives and contains hardly all essential amino acids for humans.But the most important is still aspartic acid, glutamic acid and the free amino acids as proline and lysine.Besides, protein of Royal jelly also contains some enzymes such as protease, glucose oxidase, phosphatase, cholinesterase and an insulin-like substance (Antinelli et al., 2003).Carbohydrate of Royal jelly is mainly sugars, including fructose and glucose.Fructose of Royal jelly is still more prevalent, fructose and glucose together account for 90% of the total sugars.The sucrose content varies considerably from one sample to another.Other sugars present in much lower quantities are maltose, trehalose, melibiose, ribose and erlose (Lercker et al., 1992;Daniele and Casabianca, 2012).Lipid of Royal jelly has low rate but it contains bioactive compounds (10-HDA, its isomer) rare in the nature (Morita et al., 2012;Dzung, 2013).Lipid fraction consists almost of free fatty acids with unusual and uncommon structures, with the rate of (80 ÷90) % by dry weight of lipid.They are mostly short chain (8 to 10 carbon atoms) hydroxy fatty acids or dicarboxylic acids, in contrast to the fatty acids with 14 to 20 carbon atoms which are commonly found in animal and plant material.These fatty acids are responsible for most of the recorded biological properties of Royal jelly (Schmidt and Buchmann, 1992).In addition to the free fatty acids, the lipid fraction contains some neutral lipids, sterols (including cholesterol, esgosterol) and an unsaponifiable fraction of hydrocarbons similar to beeswax extracts (Lercker et al., 1992;Hattori et al., 2007) (Fig. 1).
The research results of Ramadana and Al-Ghamdi (2012) shown that the most important nutritional compounds of Royal jelly including protein, carbohydrate and lipid have balanced rate between essential amino acids with different amino acids,  between fructose, glucose with different sugars, between unsaturated fatty acids with saturated fatty acids.This is a product that is rare in nature.They are very good for growing up and development processing of human.Therefore, the Royal jelly was called as a natural product, a very perfect product for people's health and was also called as a natural pharmaceutical product (Sabatini et al., 2009;Isidorov et al., 2011).It has the ability of anti-aging; prevent the formation of free radicals from biochemical reactions in human body.It can help prevent the heart disease or heart disorder, psychophysiological disorder, nervous disorder, digestive disorder, cancer and many other diseases.In addition, it has the capable of restoring and protecting human's skin as well as increase energy and restores health to the body.Finally, it is able to cure women of gynaecological disease.
According to analytical results in Table 1 (Dzung and Oanh, 2013), the important chemical composition of Royal jelly in Viet Nam contains many different substances but their main constituents are water, protein, carbohydrate (sugars), lipids and mineral salts.Although they occur with notable variations the composition of Royal jelly remains relatively constant when comparing different colonies, bee races and time.The analytic data can be seen in Table 1.
The Royal jelly is a pharmaceutical product that has valuable and rare.As a result, the preservation Royal jelly is a problem that is considered.Currently, the Royal jelly is preserved from the freezing method or the freeze drying method.For the freezing method, the product after freezing process is put in freezing environment that has the optimal temperature.Therefore, when time of preservation process is prolonged over 3 month, the energy consumption for 1 kg final product increase and the quality product reduce.For the freeze drying method, the product after freeze drying process is preserved at the temperature room of 25°C, when time of preservation process is prolonged over 3 month, that quality product and the energy consumption for 1 kg product are constant (Ramadana and Al-Ghamdi, 2012).
However, the freeze drying is a complicated technique including three consecutive main stages.The first stage is freezing the material; the second and the third stage are respectively the sublimation drying and vacuum drying.Both these final stages determine the quality of the product.In Fig. 2, the constituent objective functions of the freeze drying process of Royal jelly were y j , (j = 1÷4); the technological factors were Z i , (i = 1÷3).
Therefore, the problem posed here is how to determine technological factors of freeze drying process of Royal jelly, including: temperature of freeze drying chamber (Z 1 , °C), pressure of freeze drying chamber (Z 2 , mmHg), time of freeze drying (Z 3 , h) in order that the loss of nutritional compounds such as total protein (y 2 , %), carbohydrate (y 3 , %) and lipid (y 1 , %) in final product after freeze drying reduce the minimum value, with the residual water content of the final product (y 1 , %) under 4.5%.On the other hand, this product can also be prolonged time of using and export but their quality is still constant, (Dzung, 2012a, b).A problem is considered here is: If the residual water content of the final product of Royal jlley after freeze drying is higher than 4.5%, the microorganisms will be capable to grow and develop and damage products.On the other hand, if residual water content of the final product is lower than 4.5%, activity of water inside the final product will be enough for existing and development of microorganisms (Wytrychowski et al., 2013).
As a result, the aim of this study is building and solving the multi-objective optimization problem of freeze drying process to determine technological factors in order that the loss of protein, carbohydrate and lipid Fig. 2: Diagram of subjects of freeze drying process of Royal jelly in final product of Royal jelly reach the minimum value and the residual water content of the final product of Royal jelly after freeze drying is under 4.5% (Dzung, 2012b).

Materials:
The Royal jelly is harvested from bees's nest to grow up at Bao Loc area in Lam Dong province of Viet Nam.It is the pure natural product and does not mix any chemical composition.It is very thick solution.The basic composition of Royal jelly is presented in Table 1 (Dzung and Oanh, 2013).
Before the freeze drying, Royal jelly is frozen at the optimal freezing temperature in order that water in Royal jelly is completely crystallized.Acorrding to research result of Dzung (2014), it was obvious that when Royal jelly is frozen and reach temperature of-18.33°C,at the time, water inside Royal jelly was completely crystallized ω = 1 or ω = 100%.

Methods:
The method is used in this study as follow (Dzung, 2012a, b): • Determining the temperature of environmental freeze drying (Z 1 , °C); the pressure of environmental freeze drying (Z 2 , mmHg); the time of freeze drying process (Z 3 , h) of Royal jelly by the automatic measure and control system on computer of the Freeze Drying System DS-3.• Determining the residual water content of the final product (y 1 , %) by the mass sensor controlled by computer, (Dzung, 2012a, b): • Determining the total protein in Royal jelly before and after freeze drying by the Kjeldahl method (FAO, 1986).• Determining the total carbohydrate in Royal jelly before and after freeze drying by the hightperformance anion-exchange chromatography method (TCVN 4594: 1988).• Determining the lipid in Royal jelly before and after freeze drying by the the Soxhlet method (FAO, 14/7, 1986).• Determining the loss of total protein, total carbohydrate and total lipid of the final product (y j , %) by Eq. ( 2), with j = 2, 3, 4: where, the total protein, carbohydrate and lipid of the material initial and after freeze drying respectively m 1 (%) and m 2 (%) were calculated according to weight of dry matter.The fact that the product achieves the best quality means y jmin = 0.In fact, y j >0.
• Using quadratic orthogonal experimental planning method (Dzung, 2012a, b) to build the mathematical models.Relationships between the loss of total protein, carbohydrate and lipid, the residual water content of the final product and  technological factors (x 1 , x 2 , x 3 ) were written by the Eq.(3) as follow (Dzung, 2012a, b): These variables x 1 , x 2 and x 3 were coded by variables of Z 1 , Z 2 and Z 3 presented as follow: where, The experimental number is determined: The value of the star point: ( ) ( ) The condition of the orthogonal matrix: ( ) • Using the restricted area method (Dzung, 2012b) to solve the multi-objective objective optimization problem in the freeze drying process of Royal jelly.• Using the mathematical tools to solve the optimization problem in freeze drying process Royal jelly and the mathematical models describing the relationships between the loss of total protein, carbohydrate and lipid inside the final product, the residual water content of the final product of Royal jelly after freeze drying.

RESULTS AND DISCUSSION
Building the mathematical models about relationships between the loss of total protein, carbohydrate and lipid, the residual water content of the final product with technological factors of the freeze drying process: The constituent objective functions of the freeze drying process including the residual water content of the final product of Royal jelly after freeze drying (y 1 , %), the loss of protein (y 2 , %), carbohydrate (y 3 , %) and lipid (y 4 , %) inside final product of Royal jelly of freeze drying process depended on the technological factors, including: temperature of freeze drying chamber (Z 1 , °C), pressure of freeze drying chamber (Z 2 , mmHg), time of freeze drying (Z 3 , h).These constituent objective functions was determined by the experimental planning method with the quadratic orthogonal experimental matrix (k = 3, n 0 = 4).In addition, the experimental factors were established by conditions of the technological freeze drying (Dzung, 2012a, b and2013), they were summarized in Table 2.
The experiments were carried out with all of the factor levels in Table 2 to determine the value of the objective functions that describe relationships between the loss of total protein, carbohydrate and lipid inside final product of Royal jelly after freeze drying, the residual water content of the final product of Royal jelly after freeze drying and technological factors.The results were summarized in Table 3 (Dzung, 2012a).
The mathematical models of regression equations below were obtained after processing the experimental data, calculating the coefficients, testing the significance of the coefficients by the Student test and testing the regression equations for the fitness of the experimental results by Fisher test (Dzung, 2012a, b and2013) as follow: • Methematical model of the residual water content of the final product: • Methematical model of the loss of total protein inside the final product: • Methematical model of the loss of carbohydrate inside the final product: • Methematical model of the loss of lipid inside the final product: Testing the fitness of the mathematical models (8), ( 9), ( 10) and ( 9) by Fisher criterion, it shown that these equations were completely compatible for the experimental data.They describe quite suitable relationships between the loss of total protein, carbohydrate and lipid inside final product of Royal jelly, the residual water content of the final product of Royal jelly and technological factors of the freeze drying process.Therefore, it can be used to determine the optimal technological mode of the freeze drying process.

Solving the one-objective optimization problems:
Determining the technological mode of freeze drying or the optimal technological factors in order that the loss of total protein (y 2 ), carbohydrate (y 3 ) and lipid (y 4 ) inside final product of Royal jelly of the freeze drying process reach the minimum value.And the residual water content of the final product (y 1 ) reaches the minimum value but under 4.5%.It is easily obvious that this is the multi-objective optimization problem.However, the one-objective optimization problems must be solved to find the optimal utopian plan (or the utopian plan).If all the one-objective optimization problems have the same root, i.e., The utopian plan exist, the same root of all the one-objective optimization problems will be the optimal root of the utopian plan, this optimal root is the optimal of the multi-objective optimization problem and the optimal technological factors effect on the loss of total protein, carbohydrate and lipid inside final product of Royal jelly of the freeze drying process is found out by this optimal root.On the other hand, if all the one-objective optimization problems don't have the same root, i.e., The utopian plan does not exist, the multi-objective optimization problem will be established and solved to find the optimal Pareto root and the optimal Pareto plan.With this optimal Pareto root will determine the optimal technological factors of the freeze drying process of Royal jelly.
Solving the multi-objective optimization problem by the restricted area method to determine the optimal technological factors of the freeze drying process: The experiment established 4 objective functions to describe the residual water content of the final product, the loss of total protein, carbohydrate and lipid in Royal  Testing the results of multi-objective optimization problem by experiment: The freeze drying process of Royal jelly was carried out at the optimal root: temperature of freeze drying chamber of Z 1 opt = 24.35°C,pressure of freeze drying chamber of Z 2 opt = 0.368 mmHg and time of freeze drying Z 3 opt = 19.225h.The experimental results were determined the residual water content of the final product of Royal jelly and the loss of total protein, carbohydrate and lipid in Royal jelly after the freeze drying as follow: y Ex = (y 1Ex = 3.59%; y 2Ex = 2.042%; y 3Ex = 1.934%; y 4Ex = 1.826%).It was very noticeable that the experimental results bring into comparison with the optimal Pareto effect y p R = (y 1P R = 3.510; y 2P R = 1.968; y 3P R = 1.839; y 4P R = 1.799) is completely approximate.The causes lost total protein, carbohydrate and lipid in Royal jelly after the freeze drying not for temperature of environment freeze drying, pressure of environment freeze drying or time of freeze drying process but for sublimation of ice inside freezing Royal jelly.When ice inside freezing Royal jelly sublimate, ice exchange to moisture, after that moisture is attracted and removed by vacuum pump go out sublimation chamber.Besides, some substance such as protein, lipid, glucid, ash, free fat acids and so on will be attracted in this process.With the loss of total protein, carbohydrate and lipid in Royal jelly after the freeze drying lower than 3% and the residual water content of the final product of Royal jelly under 4.5% was suitable for requirement of the technological freeze drying.Consequently, the optimal Pareto root of multiobjective optimization problem of the freeze drying process of Royal jelly was possibly applied to determine the technological mode of the freeze drying process of Royal jelly in the industrial production (Wytrychowski et al., 2013).

CONCLUSION
The above results could be concluded that the mathematical models of Eq. ( 8), (9) (10) and (11) were built by the experiment and completely suitable for experimental data.They had well described relationships between the loss of total protein, carbohydrate and lipid in Royal jelly, the residual water content of the final product of Royal jelly and technological factors of the freeze drying process of Royal jelly.Therefore, these mathematical models were used to set up the technological mode of the freeze drying process of Royal jelly (Holman, 1986;Gebhart, 1992).
The loss of total protein, carbohydrate and lipid in Royal jelly after the freeze drying are lower than 3%.While the residual water content of the final product of Royal jelly after the freeze drying lower than 4.5%.It proved that final product of freeze drying process of Royal jelly had very good quality.As a result, this product makes material in order to produce pharmaceutical product (Wytrychowski et al., 2013).

Fig. 1 :
Fig. 1: The royal jelly product in Viet Nam

Apparatus:
Equipments used to research the loss of total protein; carbohydrate and lipid in final product of Royal jelly after freeze drying are listed as follow (Dzung, 2012a, b): • Determining weigh of Royal jelly by Satoriusbasic Type BA310S: range scale (0÷350) g, error: ±0.1g = ±0.0001kg.• Determining temperature of Royal jelly Dual Digital Thermometer: range scale (-50÷70) °C, error ±0.05°C.• The Freeze Drying System DS-3 (Fig. 3) that was controlled automatically by computer.It could reduce the temperature of freezing environment to (-50 ÷ -45) °C.The temperature, pressure and time profile of freeze drying process are measured by computer.• Equipment used to analyse protein, carbohydrate and lipid and the loss of protein, carbohydrate and lipid in Royal jelly after freeze drying was Kjeldahl Equipment and Soxhlet Equipment.It was shown in Fig. 4a and b.

Fig. 5 :
Fig. 5: The residual water content of Royal jelly after freeze drying was expressed in 3D

Fig. 9 :
Fig. 9: The loss of carbohydrate in Royal jelly after freeze drying was expressed in 3D

Table 1 :
The composition of Royal jelly in Viet Nam

Table 2 :
The technological factors levels design Levels

Table 3 :
The experimental data of the loss of total protein, carbohydrate and lipid according to the degree-2 orthogonal experimental matrix with