A Comparative Study on the Carbohydrate pro ile and In-vitro Glycaemic Index of Processed Basil (Ocimum basilicum) Seeds Incorporated Idlis

The tiny black Ocimum basilicum seeds, also called as basil or sabja seedsaid to keep blood sugar levels under control by decelerating the carbohydrate conversion into glucose, a simple sugar. Raw and Steamed Ocimum basilicum seeds in the proportions of 5% (RV1, SV1), 10% (RV2, SV2), 15% (RV3, SV3) and 20% (RV4, SV4) of the black gram have been incorporated in the idli formulation. The results depicted that as the proportion of O.basilicum seeds increased the total carbohydrate and sugar values showed a decline, whereas the cellulose, hemicellulose and resistant starch values increased. At 120 minutes, the mean in vitro glycaemic index of the control idli was estimated to be 66.45 ± 0.03, while the mean estimated glycaemic index value of raw O.basilicum seed incorporated variations of idli namelyRV1, RV2, RV3 andRV4 were 55.09± 0.02, 53.19± 0.02, 51.44± 0.01 and 48.09± 0.01 respectively. Themean estimated glycaemic index value of steamed O.basilicum seed incorporated variations of idli SV1 was found to be 62.72± 0.01, SV2 was 60.43± 0.01, SV3 was 58.16± 0.02, and SV4 was 56.63± 0.02 at 120 minutes. Hence it is opined that the 20% raw O.basilicum seed incorporated idli is very much low in estimated G.I values can be used in idli preparation as ameans to offer a lower glycaemic index to the obese, diabetic and cardiac disorder populations.


INTRODUCTION
Glycaemic Index indicates the rate at which the blood sugar levels raise after ingestion of a particular food in an observed period of time in comparison with the controls like glucose or white bread. The glycaemic index (GI) is considered as an important indicator of glycaemic response (Jenkins et al., 1981). Diets with a low GI are associated with decreased glycaemic response and proves bene icial for lower and more consistent postprandial insulin release, reducing body weight, total body fat and visceral fat, levels of pro-in lammatory markers and the occurrence of dyslipidemia and hypertension (Feliciano et al., 2014). (Salari-Moghaddam et al., 2019), observed a signi icant positive association between dietary GI and abdominal obesity, especially in women. The study result of (Zafar et al., 2019) has proved that the low-GI diets reduce glycated hemoglobin (HbA1c) levels, fasting blood glucose levels, BMI, total cholesterol, and LDL, but had no effect on fasting insulin, HOMA-IR, HDL, triglycerides, or insulin requirements. Even with these limitations, GI continues to capture the attention of physicians and nutritionists alike as it does offer a rational way of ranking carbohydrate-containing foods that has the potential to favorably affect the prevention and management of diabetes (Madhu, 2017). Idli, a South Indian staple diet which had been into controversies in recent times, has been acknowledged as a wholesome, nutritious food by many health professionals. As it is a steamed food product, the ease in digestion brands idli as a signi icant diet from infants to geriatrics. The issue of concern in idli is that it is categorized as a high glycaemic food with GI around 69, making it un it for diabetics to consume. Hence, several food scientists have taken the initiative to modify the GI of idli by processing the rice used for idli preparation (Chelliah et al., 2019), replacing the quantity of rice with millets lower the G.I. of idli (Nazni and Shalini, 2010).
Research study on the addition of jowar to idli has shown a low glycaemic response compared to rice Rawa idli (Jahan et al., 2018). Researchers have substituted amaranth grain lour (Nazni et al., 2014), oats and guar gum lour (Giri et al., 2017) to lower GI of idli and enhance its nutritional value making idli an ideal diet even for people suffering from non-communicable diseases. Phytomedicine the ield that utilizes plants and its parts for medicinal purposes in the treatment and prevention of non-communicable diseases especially diabetes has a long history compared to the conventional medicine (Choudhury et al., 2018).
One such noteworthy plant species, basil comes from the Greek basileus or "king. The bene its of O. basilicum include improving glucose homeostasis and lipid pro iles for patients with diabetes, strengthening of the immune system, alleviating stress and anxiety, enhancing memory, Oral and skin health and healing (Singletary, 2018). The presence of polyphenols and lavonoids showcases O. basilicum seeds as a vital part of the daily food regime (Sestili et al., 2018). With these glimpses of review of literature, it was decided in our study to incorporate the seeds of Ocimum basilicum in the idli formulation and read its impact on the carbohydrate pro ile and estimated glycaemic index of value-added idlis.

Procurement and Processing of Raw Material
The raw materials required for the study such as parboiled rice, dehulled black gram and basil or sabja seeds (Ocimum basilicum L.) were purchased from the local market of Salem district, Tamilnadu. The ingredients rice and black gram were hand sorted, to make sure that only quality grains are used and the impurities were removed by washing with water. The basil seeds were hand-sorted and sieved to ensure quality. The seeds required for preparing idlis by incorporating steamed O. basilicum seeds were steamed for 8-10 minutes.

Formulation of Raw and Steamed Ocimum basilicum L. Seeds Incorporated Idlis
The cleaned, parboiled rice and dehulled black gram were soaked for 5 hrs in the water at room temperature separately in the ratio of 4:1 (Ghosh and Chattopadhyay, 2011), for control and in different proportions for respective variations of idli as shown in Table 1 and ground to batter. The batter was allowed to ferment for 7 hours (Nagaraju and Manohar, 2000). The batter was beaten well, raw and steamed Ocimum basilicum seeds in the proportions of 5% (RV1, SV1), 10% (RV2, SV2), 15% (RV3, SV3) and 20% (RV4, SV4) were incorporated into the respective proportions of batter and was allowed to stand for 15 minutes (Samateh et al., 2018) for the seeds to gel. The batter was poured in an idli steamer and steamed till doneness which approximated to 5 to 8 minutes. Simultaneously the control idli was prepared by following the same procedure without the addition of basil seeds.

Determination of Carbohydrate pro ile
The control idli and developed variations of raw and steamed O. basilicum seeds incorporated idli were subjected to estimate the carbohydrate proile indices namely total carbohydrate, sugars, cellulose, hemicellulose and resistant starch. Carbohydrate and sugar content was assessed by IS 1656 and IS 6287 procedures respectively, while cellulose, hemicellulose and resistant starch in the idli samples were analyzed using the standard procedure by (Mathews et al., 1993;AOAC, 2002).

Estimation of In Vitro Glycaemic Index
Starch Hydrolysis percentage, (C∞ %) corresponds to the concentration at equilibrium (t 120 ), and k is the kinetic constant. Hydrolysis index (HI) is calculated as a percentage of the total content of glucose released is compared to the standard glucose that is released between 0 and 180 minutes (Barine and Yorte, 2016). The estimated glycaemic index (EGI) was calculated using the equation, EGI = 39.71 + (0.549HI)

Statistical analysis
All experiments in the present analysis were conducted in triplicate, and mean values were reported. The descriptive statistical analyses were performed using IBM SPSS Statistics 16 Software package. The data were subjected to analysis of variance (Oneway ANOVA) with Duncan's Post Hoc test (P<0.05) to determine the signi icant difference between the means.

Determination of Carbohydrate pro ile
Carbohydrate pro ile is an important parameter to determine the quality of food. Based on the quantity and quality of carbohydrates in the foods consumed, certain foods prompt a marked increase trailed by a more or less fast fall in blood glucose, while others produce a smaller peak along with a steadier decline in plasma glucose (Kumar et al., 2018). incorporation and processing whether the raw or steamed variety of seed. Next to control the amount of carbohydrate was more in 5 % raw seed incorporated variation of idli (RV1) and the least amount of carbohydrate was present in the 20% steamed seed incorporated variation of idli (SV4). In terms of the sugar content, as the proportion of the seed incorporation increased, the sugar content of the idlis decreased. This decrease in the carbohydrate and sugar content in steamed variation may be due to the fact that during wet heat treatment processes, there is a considerable loss of low molecular weight carbohydrates (FAO, 1997).
This effect is also similar to the study on sweet potatoes, where the starch content decreased on steaming (Wei et al., 2017). The non-starch polysaccharides cellulose and hemicellulose values and the resistant starch values were directly proportional to the seed incorporation levels. On comparing the variations of idlis based on the processing, more cellulose, hemicellulose and resistant starch content were observed in 20% raw O. basilicum seed incorporated variation of idli (RV4) than the 20% steamed O. basilicum seed incorporated a variation of idli (SV4). The study by (Cui et al., 2012) has also reported that on exposure to steam, the cellulose and hemicellulose content decreased sharply.

Estimation of In Vitro Glycaemic Index
The in-vitro measurements are simple, and economical when compared to in vitro tools and will be a reliable indicator of the required values, and may act as a pilot screening method to in-vivo measurements (Argyri et al., 2016). basilicum seeds incorporated variations of idlis had a low EGI value. The results of this study is similar to the study that con irms, that wet heat gelatinizes starch to a greater extent than dry heat and found to be associated with higher GI values (Widanagamage, 2013).
The processing methods, to a greater extent, impacts the EGI values. The EGI values of roasted O. basilicum seeds incorporated idli ranged from 56.73% to 56.22% (Arivuchudar and Nazni, 2020). The AUCs of digested starch over 2 hours were signi icantly lower for the raw O.basilicum seeds incorporated variations. The measure of Area Under the Curve (AUC) provides an integrated expression of insulin levels over time, so as to best assess the degree of increase in insulin levels (Allison et al., 1995).
Also, the AUCs, calculated HI and Estimated GI values can be correlated with the resistant starch values too. The more the resistant starch in the variations, the lower is the EGI value of those variations of idli. The low GI, as well as high resistant starch, reduces the insulin resistance by lowering the blood glucose levels in diabetic patients as well improves the lipid metabolism and prevents cardiovascular diseases (Kannayiram et al., 2020). To summarize, the incorporation of 20 % raw O.basilicum seeds has resulted in a low glycaemic idli compared to all the other developed products. It should also be pointed out that the methanolic extract of O. basilicum seed has proved effective for the treatment of diabetes and lipid-lowering activities in streptozotocin induced diabetes rat (Parikh and Kothari, 2020).

CONCLUSION
Though, O. basilicum seeds owing to their pharmaceutical properties, have formed a major fragment in the treatment of many ailments especially in Chinese medicine, the inclusion of O. basilicum seeds as a routine food is not in practice. Hence, in order to familiarise the O.basilicum seeds, they were incorporated into the much familiar and routine food, Idli. The presence of mucilage, a rich source of hydrocolloid with outstanding functional properties, has helped in developing idlis of desired texture. From the study conducted, in vitro starch hydrolysis of all the variations of the idlis were signi icantly affected (p < 0.05) by the process used (raw & steamed seeds) and the proportion of O. basilicum seeds added in the formulation. Resistant starch content increased signi icantly (p < 0.05) in 20% variations of raw and steamed O. basilicum seeds incorporated variations, compared with the control. It was also found that resistant starch content is inversely related with a hydrolysis index value, which resulted in lower estimated glycaemic index values in idlis with higher incorporation level of O. basilicum seeds. On comparing the raw and steamed O. basilicum seeds incorporated variations of idli, it can be concluded that all the variations of raw O.basilicum seeds incorporated idlis had a lower G.I value, while 20% of incorporation exhibited the least Estimated Glycaemic Index value. Thus, the idli (control) with medium glycaemic index value has been transformed to low Glycaemic idli because of incorporation of 20% raw O. basilicum seed.
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