The impact of the enrichment of oyster and mussel powder on antioxidant capacity and in vitro protein digestion of white-rice crackers : A Dissertation submitted in partial fulfilment of the requirements for the Postgraduate Certificate in Applied Science at Lincoln University

Abstract

Crackers are one of the most popular ready-to-eat foods due to their affordable price, long shelf-life, as well as crunchy texture. However, they contain high levels of digested starch, fats, and low levels of protein, antioxidant capacity, as well as dietary fibre. Oysters and mussels are well known protein sources and possess relatively high antioxidant capacities. The aim of this research was to develop a high-protein cracker which exhibited strong antioxidant capacity. Results showed that the crude protein content increased by more than 6 g/100g in the crackers enriched with 20% mussel, or oyster, powder and that the protein digestibility was enhanced by in excess of 4%. The addition of oyster, or mussel, powder significantly increased the total phenolic content and antioxidant capacity of crackers, with values rising from 167.43 µmol TE/g to 1049.01 µmol TE/g and from 0.744 to 1.17 mmol Trolox/g, respectively. What is more, pasting viscosity showed an upward trend with increased addition of oyster or mussel powder in crackers, whereas starch content decreased. The latter result was probably due to the additional lipids present in oyster and mussel powder and their effects of increasing viscosity of the system. Overall, formulated crackers consist of higher nutritional values compared with plain white rice crackers which can be a potential antioxidant food product.