Utilization of industrial waste of amla and apple pomace for development of functional biscuits: Physical, microstructural, and macroscopic properties

Abstract

Food waste utilization using technological innovations can aid in addressing food waste issues. Thus, this study aimed to develop functional biscuits enriched with apple, amla, and apple–amla mix pomace (Industrial waste). The knowledge of the rheological properties of dough was considered during biscuit development. Besides, the effect of various combinations of apple, amla, and the mix pomace (5%–20% with 5% increment) on physical, textural, sensory, and microstructural characteristics of the functional biscuit was investigated. X-ray microcomputed tomography (X-ray μCT) scanning coupled with image analysis was used for microstructural characterization. The textural attributes and color characteristics of the functional biscuits were significantly different compared to the control sample. The dough formulation (pomace) and variation in microstructure properties significantly affected the physical, textural, and sensory properties. Furthermore, a remarkable reduction in the total volume (up to 25.4%) and total surface area of pores (up to 45.5%) of functional biscuit was noted. The volume fraction of solid phase showed an increasing trend as the composition of pomace rises and the porosity reduced drastically from 37.24% in control sample to 17.48% in apple–amla mix 20% sample. Three-dimensional images of biscuits analyzed by an X-ray μCT system also supported the quantitative results. The functional biscuit prepared by partial replacement of wheat flour by 10% amla pomace is best in dough rheology, microstructural, textural, and sensory attributes. In conclusion, amla, apple, and mix pomace biscuits enhance the nutritional, functional, and overall characteristics of the sample. The results of this study aid in utilizing waste (pomace) of the amla and apple industry into a valuable dietary product. Novelty impact statement The study is one of the few studies on apple and amla pomace and their utilization for functional food product development. Also, the effect of amla and apple pomace composite on biscuit preparation is a novel work. The replacement of apple and amla pomace up to 10% for biscuit preparation was desirable. At 20% replacement, the color, texture, internal structure, rheological properties, and sensory characteristics of developed biscuits were not desirable. X-ray microcomputed tomography (X-ray μCT) coupled with image analysis technology is novel in food processing. The internal structure analysis of biscuits prepared was very helpful in correlating various properties. The development of functional food from waste generated by the fruit processing industries can improve the economy of the industry at the same time, the environmental pollution problem can also be tackled.