Abstract

This study aimed at demonstrating the stabilizing effect of up to 0.4% (wt/wt flour) of rosemary spice (Rosemarinum Officinalis L.) in a flour-based protein-rich product intended for young children. The flour was made of full-fat soya flour, meat (beef) powder, and carrot flour as β-carotene source. Analysis was done for proximate composition, β-carotene content, microbial load and sensory evaluation for rancidity over time. Different levels of rosemary spice salvaged a net of 3.42 - 3.83 mg/100 g of β-carotene within a storage period of 7 weeks at 35°C accounting for up to 18% of β-carotene sparing as compared to the non-spicy sample. There was, however, no evidence of increased protection of β-carotene with increase in rosemary spice concentration. Rancid odors and flavour were detected in samples with spice, latter than in samples with no spice. Rosemary spice exhibited up to a net of 38% reduction in microbial load in spicy samples as compared to the non-spicy sample. In a protein, fat and β-carotene rich flour-based product, rosemary spice exhibits triple stabilizing action. The phenolic compounds (rosemarinic, carnosol and carnosic acid) in rosemary spice limits β-carotene degradation and decelerates the production of secondary products of lipid oxidation while the terpene fractions are implicated for halting the proliferation of micro-organisms.

Key words: Rosemary spice, high protein β-carotene-rich flour, antioxidant effect, antimicrobial effect.