Protein profile and physicochemical properties of Liluva (soaking, boiling and sprouting water) from three food legumes : A dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science at Lincoln University

Abstract

Legume waster water has been revealed to contain sufficent nutritional value as an industry by-product. In this study, physicochemical properties and protein profile of pea, chickpea and soybean soaking and cooking water were investigated. Among the three legumes isolates with their wastewater, all of the cooking wastewater exhibited the lowest content of free amino acid. In the yellow pea free amino acid assay, the soaking method contains the highest volume of Ser (6.00mg/g), His (6.01 mg/g), Phe (7.48 mg/g), Ile (4.12mg/g) Thr (4.27 mg/g) and Met (1.68mg/g). Chickpea soaking water has the highest volume of His (12.05mg/g) Phe (16.43mg/g), Ile (9.77mg/g), Thr (10.12mg/g) and Met (11.08mg/g). Pea cooking water Met to Lys is 0.8, which gave it the most elastic properties to form the sponge cake and more nutritional value. To identificate the emulsifying properties, oil-in-water emulsions containing 50% Canola oil were prepared using the legumes wastewater (pea, chickpea and soybeans). These emulsions were then stored at 4°C, and changes in particle size were monitored throughout storage. Chickpea cooking emulsions showed the smallest droplets distribution in the original emulsions. The mean emulsion droplet diameter (nm) evaluated differed significantly(p<0.05) for all centrifugated legume wastewater-based emulsions. Different types of legumes affected emulsifier stability because of different protein content. In conclusion, soybean soaking and cooking water have the best emulsifier stability both at room temperature and the refrigerator temperature, pea cooking water was investigated to form the hardest sponge cake because of its highest protein content.