Development, Characterization and Shelf Life Optimization of a Prototype Nutrient Dense Food Bar

Abstract

The Indian vetch (Lathyrus sativus L.) and chickpea (Cicer aritenum) were selected for nutritional profile augmentation of food bars. Various processing techniques were used to reduce antinutritional factors in these legumes. The prepared bars were characterized for their nutritional quality attributes. Different antioxidant extracts were screened for their antioxidant activity. Response Surface Methodology (RSM) was used to optimize their levels in nutrient dense food bar during four months storage. The natural fermentation decreased crude protein level of legumes during processing, however other main constituents i.e. crude fat, total ash and crude fiber were least affected. The antinutritional factors i.e. trypsin inhibitors, tannins, polyphenols, phytates and β-ODAP (in Indian vetch only) were reduced effectively by fermentation and germination processes. The HClextractability (an index of bioavailability) of minerals in processed and raw Indian vetch and chickpea flours varied considerably in all cases. The processing treatments inserted positive influence over this. As part of criteria for selection of best treatment for nutrient dense food bar making, in-vitro protein and starch digestibilities, sensory characteristics, proximate composition and calorific value were analysed. In-vitro protein digestibility (IVPAD) and in-vitro starch digestibility (IVSD) for nutrient dense food bars were improved by the incorporation of processed Indian vetch and chickpea flours. All of the sensory attributes especially flavor, taste and overall acceptability deteriorated on the incorporation of natural fermented flour in food bars, whereas controlled fermented flour containing bars were preferred. The proximate composition data showed that bars with Indian vetch flour contributed high portion of crude protein and fat, whereas chickpea bars contributed marginally less. This investigation showed that these food bars are calorific dense as well by the virtue of their rich nutrient levels. The processed flours were thereafter blended with other protein sources to produce balanced protein meal. The protein quality of these diets was assessed by implying in-vivo rat assays. The values for relative protein efficiency ratio (RPER) and relative net protein ratio (RNPR) in close proximity to each other for processed meals acted as an indicator for good protein quality of these meals. The food bar meals showed significant variation among samples for isoleucine and sulfur containing amino acids i.e. methionine and cysteine. High contents of these amino acids were studied in meals carrying chickpea flours. When this amino acid profile was compared with amino acid requirement criteria for 2-5 years old children, it matched well. High TPD was achieved by food bars carrying controlled fermented Indian vetch and chickpea flour meals, followed closely by germinated flour possessing meals. The computed PDCAAS value was 1 for aforementioned meals. Food processing waste materials were extracted using different solvents and ethanol 80% solution in water was found effective in extracting all materials. Higher values of total polyphenol content were achieved by pomegranate peel among all solvent extracts, whereas DPPH scavenging and β-carotene bleaching capacities was also much better in pomegranate peel extracts than extracts from other materials. Then food bars were prepared taking into account the best formulation, incorporating Emblica officinalis extract, Punica granatum peel extract and citric acid at different levels for shelf stability of nutrient dense food bar. The second-order polynomial models were fitted well for independent variables on storage data at various intervals. It was observed that the optimized levels of Emblica officinalis (1.05%), Punica granatum extract (1.86%) and citric acid (0.059%) in food bar formulation generated through using Response Surface Methodology, resulted in sensory acceptable and shelf stable nutrient dense food bars.