Fiber rich snack food products incorporated with green gram husk and their suitability for diabetics

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1 Asian J. Dairy & Food Res, 34(4) 2015: Print ISSN: / Online ISSN: AGRICULTURAL RESEARCH COMMUNICATION CENTRE Fiber rich snack food products incorporated with green gram husk and their suitability for diabetics Preeti Bora* and Kalpana Kulshrestha Department of Foods and Nutrition, College of Home Science, G.B. Pant University of Agriculture and Technology, Pantnagar , Uttarakhand, India Recieved: Accepted: DOI: /ajdfr.v34i ABSTRACT A major by-product of dal mills is pulse husk which is basically used as ruminant feed. Its nutritional significance in human diet is less known. Keeping in view that pulse husk is a rich source of dietary fiber, the present study was undertaken to formulate various recipes of snack food items using green gram husk in varied proportions. The husk was incorporated in different traditional snack food item recipes viz., bread, biscuit, muffin, mathri and pakora in varying proportions (5-15 per cent) and the of different husk incorporated products was tested through sensory evaluation by score card method for different sensory qualities. The best accepted product was evaluated for various nutritional parameters and glycemic index. The results indicated that among all the food items prepared biscuit with 12.5 per cent of green gram husk found to be most acceptable. It was further evaluated for nutrient composition and glycemic response in normal subjects in the age group of years. Appreciable amount of iron (23.75 mg/100g), calcium ( mg/100g) and total dietary fiber (14.98%) content was seen in fiber rich biscuits. The glycemic index of fiber rich biscuits (46.26) was significantly low than the control biscuits (68.70). Thus the green gram husk incorporated biscuits with high dietary fiber and low glycemic index can be recommended for inclusion in the diet of people suffering from diabetes and constipation. Key words: Green Gram Husk, Dietary fiber, High fiber food products, Glycemic index. INTRODUCTION The Indian sub- continent depends on pulses as sources of proteins, minerals and vitamins in the daily diets of the people. Among these, green gram (Vigna radiata L.) is known for its easy digestibility, low flatulence potential and high protein content (Venter and Eyssen, 2001). Plant foods are the only sources of dietary fiber. All fractions of dietary fiber are the major structural components of plant cell wall. The total dietary fiber (TDF) is further sub divided into soluble and insoluble dietary fiber depending on their solubility in water. Lignin, cellulose and some components of hemicellulose form the insoluble dietary fiber (IDF). Major components of plant gums, - glucans, hemicellulose, pectin and mucilaginous matter are called soluble dietary fiber (SDF) (Rao and Ramulu, 2003). Dehusking of the whole grain pulses to dals bring about a significant reduction in total dietary fiber (TDF) ( %) as well as in insoluble dietary fiber (IDF) ( %). The decrease in TDF content of dals over those of whole grain pulses was mainly due to the decrease in their IDF content. This indicates that the fiber present in the husk of whole grain pulses is mainly IDF. The amount of IDF as percentage of TDF constitutes 85-89% in whole grain pulses (Rao and Ramulu, 1998). *Corresponding author s borapreeti@gmail.com. High dietary fiber content of pulses postulated to have important physiological effects. Pulses also have low glycemic index, which makes them valuable foods for diabetics (Ofuya and Akhidue, 2005). The seed coat of mung bean is high in crude fiber which is lowered when the seed coat is dehusked. So, the husk may provide a large amount of dietary fiber which has many health benefits. Beneficial effects of dietary fiber have been attributed to its role in modifying some of physiological activities in the body. Increased fecal bulk and improved large bowel function, reduced glycemic response to meal, delayed absorption of cholesterol, reduced blood pressure, enhanced weight control, reduced risk of certain forms of cancer and improved gastrointestinal function are major beneficial effects attributed to adequate consumption of dietary fiber (Anderson and Patterson, 2000). Pulse husk is also considered as rich source of minerals. Among the several agro-industrial by-products available, pulse husks form major resources in terms of availability. Large quantities of pulse husks are available as by-product while processing the pulses in the mills. Pulse husks are available to the extent of 3 million tons in India

2 per annum (Ravi et al., 1999). In the recent years, the uses of legume husks gain importance as the ingredients in the formulation of various food products. Moreover, the husk of legumes is potentially low cost and largely available (Inam et al., 2010). Food items like mathri, pakora, biscuits, bread and muffins are important part of snacks consumed by people. So considering the pulse husk as good source of minerals and fiber, easily available and less popular for human consumption as a good source of fiber, the present study was undertaken to develop high fiber low glycemic index green gram husk incorporated snack food products, evaluate them organoleptically and check their suitability for diabetics. MATERIALS AND METHODS Extraction of husk from whole green gram: Whole green gram was procured from local market and cleaned free from the foreign materials. It was dipped in water, and then removed immediately so as to loose the husk. The dal is then dried overnight in a hot air oven at a temperature of C and then dehusked next day. The sample was milled in Testing Mill Type-TM05 (Satake) at Department of Post Harvest Process and Food Engineering, College of Technology, GBPUAT Pantnagar and the husk was obtained. About g of husk was obtained from 1 kg of whole green gram. The husk obtained was sieved through 85 mesh standard sieve to remove the ground dal powder. The portion of husk retained over the sieve was ground in a kitchen mixer to get a uniform powder. The husk powder obtained was stored in air tight containers. Chemical analysis of green gram husk: Chemical analysis of the green gram husk powder was done by estimating proximate composition A.O.A.C. (1975), vitamin (niacin) by method quoted by Raghuramulu et al. (2003), total dietary fiber by the method of Asp and Johnson (1981). Among minerals phosphorus was estimated colorimetrically Volume 34 Issue 4 (2015) 301 according to the method of Fiske and Subba Row as quoted by Raghuramulu et al. (2003). Calcium content in the sample was determined titrimetrically by method of A.O.A.C. (1975) as quoted by Raghuramulu et al. (2003). Estimation of total iron was done colorimetrically by Wong s method (1928) quoted by Raghuramulu et al. (2003). Manganese, zinc and copper were estimated using atomic absorption spectrophotometer by method quoted by Raghuramulu et al. (2003). Among antinutrients, phytic acid by Wheeler and Ferrel (1971), tannin by Folin-denis method given by Schanderi (1970) and oxalic acid by Raghuramulu et al. (2003) were estimated. Estimation of in-vitro bioavailability of iron was done by method of Rao and Prabhavati (1978). Formulation of green gram husk incorporated high fiber recipes: Five different snack food items with different level of husk i.e. 5, 7.5, 10, 12.5 and 15% level were prepared with basic ingredients. Food items viz. mathri, pakora, bread, biscuit and muffins were prepared under two sub-categories i.e. baked and fried using their standardized recipes. 0% level was the control against fiber incorporated recipes. The details of basic ingredients, carbohydrate content and energy contribution to the day s calorie intake of different recipes are given below. Sensory evaluation of developed products: Formulated products were evaluated for sensory characteristics such as color, texture, flavor, taste and overall using Amerine et al. (1973) score card method by a panel of 15 semi-trained judges from Department of Foods and Nutrition, College of Home Science, Pantnagar. The sensory evaluation of the food products was done in three steps as shown in the flow chart below. After evaluating the products on the basis of sensory characteristics, finally one food item from the two sub-categories i.e. baked and fried food item was selected at a particular acceptable level of green gram husk. Food product Basic Ingredients Total Carbohydrate Total calories content (gram) content (Kcal) Mathri Refined Wheat Flour: 100gVanaspati: g Salt: 2gCarom (Ajwain): 1.6gOil for frying Pakora Bengal gram flour: 100gOnion: 25gTurmeric: 1gCoriander powder: 2gRed chilli powder: gGreen chillies: 5gSalt: 5gOil for frying Bread Wheat flour: 100gCompressed yeast: gShortening: 2gSalt: 1.25gSugar: 3g Biscuit Refined Wheat Flour: 100gShortening: 20gSalt: 1gSugar: 40gBaking powder: gMilk: 10ml Muffins Refined Wheat Flour: 100gMelted Butter: gSalt: 1gSugar: 4.5gBaking powder: 1.6gMilk: 80mlEgg: 1 in no. The formulated products were evaluated organoleptically.

3 302 ASIAN JOURNAL OF DAIRY AND FOOD RESEARCH Snack Food Item at 0, 5, 7.5, 10, 12.5 and 15% level G reen gram husk + other ingredients Fried Baked Mathri Pakori Biscuit Muffins Bread SENSORY EVALUATION ONE WAY ANOVA BETWEEN DIFFERENT LEVELS OF INCORPORATION OF HUSK IN EACH ITEM OF BOTH CATEGORIES Mathri selected at particular level of husk Pakora selected at particular level of husk Biscuit selected at particular level of husk Muffin selected at particular level of husk Bread selected at particular level of husk Two way Anova was used to find the best of these two Single item selected Two way Anova used to find the best of these three Single item selected One way Anova was used to find out the best of these two* * The best selected based on sensory scores Nutritional quality of product selected: Chemical analysis of the selected fiber rich product was done by estimating proximate composition A.O.A.C. (1975), vitamin (niacin) was done by method quoted by Raghuramulu et al. (2003), total dietary fiber by the method of Asp and Johnson (1981). Among minerals phosphorus was estimated colorimetrically according to the method of Fiske and Subba Row as quoted by Raghuramulu et al. (2003). Calcium content in the sample was determined titrimetrically by method of A.O.A.C. (1975) as quoted by Raghuramulu et al. (2003). Estimation of total iron was done colorimetrically by Wong s method (1928) quoted by Raghuramulu et al. (2003). Manganese, zinc and copper were estimated using atomic absorption spectrophotometer by method quoted by Raghuramulu et al. (2003). Estimation of in-vitro bioavailability of iron was done by method of Rao and Prabhavati (1978). Glycemic index of selected fiber rich product :The glycemic response of selected food product was studied in 10 normal healthy female volunteers in the age group of years. Glucose tolerance test (GTT) was conducted on overnight fasted subjects. A 50g glucose dissolved in 200 ml water was given to the subjects. The subjects were instructed to finish glucose solution within 15 minutes and to avoid physical exertion during the experimental period. The blood glucose level was measured at 0, 30, 60, 90,120 and 150 minutes intervals with the help of Glucometer (Lifescan, One Touch Basic) using active glucose strips. On next day the volunteers were served with the test food product containing 50g carbohydrate. The food product was served with 200ml of water. The subjects were asked to follow same instructions as for glucose tolerance test. The blood glucose was measured initially and at 30, 60, 90,120 and 150 minutes of finishing the food product. The blood glucose response curves were plotted for both glucose and test food. With the help of the graph, the postprandial incremental areas were calculated and the glycemic response of food product was calculated according the formula given by Wolever (1990). (Incremental area under blood glucose reponse curve for food products) GI 100 Corresponding area after equicarbohydrate portion of glucose The GI value of each individual was calculated and the average GI of 10 replicates was computed.

4 TABLE 1: Chemical analysis of green gram husk Statistical analysis: The data obtained was analyzed using statistical methods viz. computation of percentage, mean and standard deviation. To find out significant difference among the food products in different parameters of sensory scores card, one way anova and two way anova was used in different steps of green gram husk incorporated food product formulation and selection of acceptable product through sensory scores as shown in the flow chart above. Results and Discussion: Table 1 shows the chemical composition of green gram husk. The total dietary fiber content was found to be 55.44% which mainly consisted a major portion of insoluble dietary fiber (53.71%). Among the minerals green gram husk was found to have good amounts of calcium, iron and phosphorus along with high level of antinutrients too. As green gram husk is a natural food constituent and rich in minerals and having appreciable amounts of dietary fiber, it was used to formulate high fiber food products. As the cost factor of the recipes is concerned, all the food products are cost efficient and are generally consumed by the population. All the food products are prepared using standardized recipes. All the food products were evaluated on the basis of sensory characteristics. The first step of sensory evaluation in baked food products indicated that in biscuit colour, appearance and taste parameters showed no significant difference (Table 2). In flavour and overall, biscuit with 12.5 per cent level of husk had higher scores among all levels. The average scores of all sensory parameters were in the range of 7-9 which falls between good and on the basis of sensory scores; biscuit with 12.5 per cent level of husk was selected for the next step of sensory evaluation. Volume 34 Issue 4 (2015) 303 Proximate composition (%) Minerals (mg/100g) Antinutrients (mg/100g) Dietary fiber (%) Moisture 7.13 Iron Tannin Total dietary fiber Crude protein 7.69 Calcium 400 Phytic acid Insoluble dietary fiber Crude fat 2.17 Phosphorus 356 Oxalic acid 0.88 Soluble dietary fiber 1.73 Crude fiber Zinc 2.90 Total ash 3.85 Copper 0.9 Carbohydrate Manganese 2.28 Note: Values are mean±sd of four observations The results of sensory scores in bread (Table 3) showed that as the level of husk increased, the of bread was decreased and lower scores were obtained in all the parameters. There was a significant difference between all the levels in all the parameters. The average scores of all sensory parameters were in the range of 6-9 which falls between fair, good and very good suggesting their overall till 7.5 per cent for the next step of sensory evaluation. TABLE: 3 Mean sensory scores of Bread (n=15) Incorporated Control per cent per cent per cent per cent per cent sem cd at 5% 0.610* 0.669* 0.616* 0.639* 0.667* 0.723* Table 4 shows that Muffins with different level of husk were liked by the consumers up to 10 per cent level. The average scores of all sensory parameters were in the range of 7-10 which falls between good and very good and on sensory scores basis muffin with 7.5 per cent level of husk was selected for the next step of sensory evaluation. TABLE: 2 Mean sensory scores of Biscuit (n=15) Incorporated Control per cent per cent per cent per cent per cent sem cd at 5% * * 0.411* TABLE: 4 Mean sensory scores of Muffins (n=15) Incorporated Control per cent per cent per cent per cent per cent sem cd at 5% 0.722* 0.641* 0.745* 0.691* 0.609* 0.688*

5 304 ASIAN JOURNAL OF DAIRY AND FOOD RESEARCH Table 5 shows that Mathri with different level of husk showed significant difference in the parameter for overall only. The average scores of all sensory parameters fall between good and very good suggesting their overall till 10 per cent. So, on sensory score basis mathri with 10 per cent level of husk was selected for the next step of sensory evaluation. TABLE: 5 Mean sensory scores of Mathri (n=15) Incorporated Control per cent per cent per cent per cent per cent sem cd at 5% * The sensory scores of Pakora showed that among higher levels of husk, significant difference was seen in all the parameters between all levels as seen in Table 6. The average scores of all sensory parameters were in the range of 7-10 which falls between good and very good and on sensory score basis, pakora with 10 per cent level of husk was selected for the next step of sensory evaluation. TABLE: 6 Mean sensory scores of Pakora (n=15) Husk Incorporated Colour Appearance Flavour Taste Texture Overall Control per cent per cent per cent per cent per cent sem cd at 5% 0.507* 0.483* 0.455* 0.555* 0.465* 0.506* In the second step of sensory evaluation, the mean sensory scores of baked food products selected at particular level of husk were compared and results showed (Table 7) that among the baked products selected in the first step viz. biscuit with 12.5% husk, bread with 7.5% husk and muffins with 7.5% husk, muffin with 7.5 per cent level of husk scored highest in all the parameters however when these scores were compared with biscuit (12.5 per cent level), the differences in the scores of appearance, flavour and overall were found to be non-significant. So, product with maximum level of husk i.e. biscuit with 12.5% husk was selected for the next step of sensory evaluation. TABLE: 7 Mean sensory scores of selected food products in baked snack item category (n=15) Type Colour Appearance Flavour Taste Texture Overall A B C sem cd at 5% 0.668* 0.568* 0.642* * A- Biscuit with 12.5% husk B- Bread with 7.5% husk C- Muffins with 7.5% husk Among the fried food products results showed (Table 8) that among these two selected products, there was no significant difference in various parameters. Mathri with 10% husk scored higher and was selected among the two products for the next step of sensory evaluation. TABLE: 8 Mean sensory scores of selected food products in fried snack item category (n=15) Type Colour Appearance Flavour Taste Texture Overall A B sem cd at 5% A- Mathri with 10% husk B- Pakora with 10% husk In the third step the comparison of two final products i.e biscuit (12.5% level ) and mathri (10% level ) conclude that significant difference was observed in colour and texture among the selected products (Table 9). No significant difference was observed in appearance, flavour, taste and overall of the products. So, product with more level of husk i.e. biscuit with 12.5% husk was the best selected snack food product. TABLE: 9 Mean sensory scores of selected food products in both baked and fried snack food item category (n=15) Type Colour Appearance Flavour Taste Texture Overall A B sem cd at 5% 0.436* * A- Biscuit with 12.5% husk B- Mathri with 10% husk

6 TABLE: 10 Nutritional composition of green gram husk incorporated Biscuit Volume 34 Issue 4 (2015) 305 Nutrient Nutrient Nutrient Moisture Crude protein Crude fat Crude Total ash (%) (%) (%) fiber (%) (%) Carbohydrate (%) Physiological (by difference) energy (Kcal) 9.53± ± ± ± ± ± ±3.42 Iron Calcium Phosphorus Zinc (mg/ Copper (mg/100g) (mg/100g) (mg/100g) 100g) (mg/100g) Manganese Niacin (mg/100g) (mg/100g) ± ± ± ± ± ± ±0.410 Ionizable iron Soluble iron Bio-availability Insoluble dietary Soluble dietary (mg/100g) (mg/100g) of iron (%) fiber (%) fiber (%) Total dietary fiber (%) 1.47± ± ± ± ± ±0.17 Note: Values are mean±sd of four observations The snack food item selected after sensory evaluation was evaluated for the nutritional composition. 100 gm refined wheat flour was used in the preparation of biscuits. In addition to this 20 gm shortening, 1 gm salt, 40 gm sugar, 1.5 gm baking powder and 10 ml milk was also added. In husk incorporated biscuits refined wheat flour is replaced with different proportions of green gram husk. Table10 shows the nutritional evaluation of husk incorporated biscuit (12.5% level of of green gram husk). Results showed that husk incorporated biscuit found to have appreciable amount of protein, carbohydrate and energy. It contained good amount of iron (23.75 mg/100g), calcium ( mg/100g) and phosphorus (166.66mg/100g). The total dietary fiber content was found to be 14.98% which could be contributed to its high green gram husk content. Figure 1 shows the blood glucose response of developed product (Biscuit with 12.5% level of husk ) in normal healthy volunteers (n=10). The area under blood glucose response (Table 11) curve was observed to be mg. min/100ml for glucose. For control biscuit the mean area under blood glucose response curve was observed to be mg. min/100ml and for biscuit with 12.5 per cent husk it was found to be mg. min/100ml. The lower area covered by the husk incorporated biscuit is because of high level of fiber content mg min/100ml Time (min) Glucose Control Biscuit Biscuit with 12.5 per cent green gram husk FIG.1: Blood glucose response curve for control biscuit and fiber rich biscuit in comparison to glucose load of 50 g due to husk which increased its dietary fiber content. Pulses are foods with low glycemic index, since the lowest glycemic responses for starchy foods have been reported after the consumption of dried legumes (Rizkalla, 2002). From the figure it is also evident that the peak of glucose decline sharply in the case of glucose, however in the case of husk incorporated biscuits a slow decline was observed which was may be the slow and steady release of glucose which is considered very important in diabetic diets. According to the classification of glycemic index of foods (Foster and Powell et al, 2002), biscuit (12.5 per cent husk incorporated) fall under the category of low glycemic index foods, however the control biscuit is classified as medium glycemic index food (Table 11). Research studies quote that the hypoglycemic action of antinutrients like phytic acid and polyphenolic compounds like tannins that may tend to influence starch digestibility and hence lower plasma glucose and insulin concentrations (Alonso et al., 2001). The high levels of phytic acid and tannins in green gram husk may also contribute to the lower glycemic index of these products. TABLE 11: Area under blood glucose response curve for glucose, control biscuit & fiber rich biscuit and Glycemic Index of fiber rich biscuit in normal subjects Food product Area mg. min/100 ml GI (%) Glucose ± Control biscuit ± Biscuit with 12.5 % ± husk CONCLUSION Thus, from the present study it can be concluded that green gram husk could be well incorporated in different snack food item recipes and is well acceptable. Nutritional evaluation of the selected fiber rich food item revealed that the fiber rich product have good nutritional value and found to be a good source of minerals. The husk incorporated product have low glycemic index which makes it suitable for the consumption of diabetic subjects.

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