Effect of light,food additives and heat on the stability of sorghum 3-deoxyanthocyanins in model beverages

This work aimed to evaluate the stability of sorghum 3-deoxyanthocyanins (DXA) in model beverages (pH 3.5) elaborated with crude sorghum phenolic extract, containing ascorbic acid and sulphite, under fluorescent light exposure and subjected to heat treatment. There was no significant difference in the DXA degradation during storage under light exposure (24.16%) and absence of light (20.72%). DXA degradation did not differ in the presence of ascorbic acid during storage under light exposure (23.99–25.38%) and absence of light (19.87–21.74%). The addition of sulphite caused an initial bleaching reaction, but as a reversible reaction, the anthocyanin content was higher on the last day of storage compared to the first day. There were no significant differences in total anthocyanin content of all treatments subjected to the heat treatment (80 °C for 5 and 25 min). Thus, crude DXA are very stable under light, additives and heat, and may be useful as natural food colourants.     

Sweet processed foods in Brazil: use of sugar and sweeteners,inclusion of sugar claims and impact on nutritional profile

This study characterised the main sweet beverages and food products marketed in Brazil regarding (i) the addition of sugar/sweeteners, (ii) nutritional profile and (iii) sugar claims. Results revealed that most of the beverages had added sweeteners, while food products were mainly sweetened with sugar. Moreover, >90% of the powdered products had added sweeteners. ‘Zero sugar’ (46%) and ‘light’ (55%) were the most common sugar claims in sugar-free and reduced-sugar products, respectively. Powdered products, soya drinks and baked products included claims less frequently. Regarding the nutritional profile, beverages with sugar substitution had a proportionally greater reduction in the content of carbohydrates and calories (up to 99%, for both) in relation to food (<82% and <85%, respectively). The results suggest that reducing sugar in solid foods remains a greater challenge than in beverages and that this reduction has less impact on the final energy density of foods.     

The effects of blackcurrant and strawberry powder on the physicochemical and in vitro glycaemic response of starches derived from sweet potato (Ipomoea batatas) and potato (Solanum tuberosum)

Phenolic compounds have been shown to deliver numerous health benefits. Research has also shown that starch and phenolic compounds interact. This study aimed to investigate the effects of blackcurrant and strawberry powder on the physicochemical and in vitro predicted glycaemic response of sweet potato and potato starches. Sweet potato, or potato, starches were mixed with 0%, 5%, 10% and 15% (w/w) of blackcurrant, or strawberry, powder, to form blackcurrant and strawberry-enriched starch pastes. The results showed that enrichment with 5%, 10% and 15% blackcurrant or strawberry powder for sweet potato and potato starch significantly altered the pasting viscosity and colour profiles (P < 0.05), increased the phenolic content and antioxidant activities of starch pastes (P < 0.05). Blackcurrant or strawberry powders mixed with sweet potato or potato starches reduced amount of reducing sugar released during in vitro digestion. Addition of 15% blackcurrant powder for the starch exerted stronger in vitro antioxidant and hypoglycaemic properties than that of 15% strawberry powder. Collectively, these findings suggested that addition of blackcurrant or strawberry powder into sweet potato and potato starches manipulated the hypoglycaemic property of pastes.