Physicochemical and nutritional properties of high protein emulsion-type lupin-based model milk alternatives. Effect of protein source and homogenization pressure

BACKGROUND: Plant-based milk alternatives are becoming more popular. However, many are low in nutrients, particularly protein. More attention is being given to plant protein isolates / concentrates as potential ingredients in high-protein milk alternative formulations. RESULTS: The effect of lupin protein source on the physicochemical, functional, and nutritional characteristics of model milk alternatives was investigated. Milk alternatives were produced with either blue lupin or white lupin protein isolate, formulated to contain similar levels of protein and fat as low-fat cow's milk. Nutritional composition and predicted glycemic properties were measured. The effect of homogenization pressure on the physicochemical properties and storage stability was also assessed, with cow's milk and soy milk alternative analyzed for comparison. Both blue and white lupin milk alternatives were high in protein, low in fermentable oligo-,di- and monosaccharides, and polyols (FODMAPs), and had a low predicted glycemic index. White lupin milk alternatives had smaller particle size as well as greater stability, with less creaming compared to blue lupin milk alternatives, although the former showed slightly higher sediment layers. Increasing homogenization pressure from 180 to 780 bar resulted in smaller particle size, lower separation rate, and greater foamability for both blue and white lupin milk alternatives. White lupin milk alternative homogenized at 780 bar was found to be the most stable product, with a similar separation rate to cow's milk. CONCLUSIONS: These results indicate that protein source and processing can influence functional properties significantly along with product stability, and this is an important consideration when formulating high-protein milk alternatives.