Developing a carob-based milk beverage using different varieties of carob pods and two roasting treatments and assessing their effect on quality characteristics

Abstract

BACKGROUND: This work aimed at formulating a carob-based milk beverage and assessing its chemical and sensory properties. Six varieties of carob pods, each processed into roasted and unroasted powders, were used to develop 12 prototypes of the beverage. Chemical and physico-chemical analyses (moisture, ash, fibre, protein, sugars, total-phenolics, total-antioxidants, water activity and colour) and sensory tests were conducted. RESULTS: The variety of carob pod had a significant effect on all chemical variables in carob powders (P < 0.01), except for sugars, and when incorporated in the beverage, on moisture, total phenolics, total antioxidant activity and colour parameters (L, a, b; P-values<0.001). Roasting treatment significantly increased fibre, total phenolics, total antioxidant activity (P-values<0.001), fructose, glucose (P-values<0.05), and a-value levels (P < 0.01), significantly lowered moisture (P < 0.05), water activity, L- and b-values (P-values<0.001) in carob powders; and significantly increased the beverage's total phenolics, a-value (P-values<0.001) and total antioxidant activity (P < 0.01). Roasting treatment significantly increased the beverage's acceptability ratings. Beverages formulated with roasted carob powder had higher ratings for level of residue, colour, caramel odour, mocha odour and flavour, roasted coffee odour and flavour, viscosity mouthfeel and bitter aftertaste. Principal component analysis was conducted; PC1 and PC2 separated attributes according to roasting treatment and variety of carob pods, respectively. CONCLUSION: The use of Akkari roasted and Baladi Ikleem el Kharoob roasted to formulate a carob-based milk beverage is recommended. © 2016 Society of Chemical Industry.