Studies on the optical interference by potato, sorghum, wheat, pigeon pea and cowpea starch granules indicated that the potato granule was ordered mostly on the centre of the granule and that the molecular arrangement of the birefringent portion was perpendicular to the radial. This was more so with the legume starches where the entire granule was ordered. Cereal starches had birefringent material on the periphery and non‐birefringent material in the centre and in this case, the birefringent material was radially arranged.

The in vitro digestibility of native and germinated pigeon pea starches both in raw and cooked forms were investigated. The rate of digestibility (glucoamylase) was different for the two raw starches. There was a preferential utilization of low molecular weight ‘amyloses’ in the germinated samples, during in vitro enzymatic digestion of the raw granule. On acid hydrolyses, germinated samples produced lower molecular weight fragments than did raw starch, though the rate of reducing sugar released was not different. It may therefore be concluded that the size of the „amylopectin”︁ molecule is smaller in germinated starch. The easy availability of low molecular weight „amyloses”︁ may also influence the greater susceptibility of germinated starches to amylolysis even after cooking.

Gracilaria verrucosa is a red seaweed that has been widely utilized in the food andpharmaceutical industries due to its biological properties. The utilization of biologicalagents in obtaining certain bioactive compounds would confront unavoidable issues,particularly its bioactive sustainability. Hence, microbial fermentation has been reported as a practical approach to maintaining bioactive production and boosting its properties. Our study aimed to evaluate the potential of marine yeast Aureobasidium melanogenum MTGK.31 as a fermenting agent for G. verrucosa and characterize the seaweed metabolite profile and antioxidant activity after fermentation. The seaweed was fermented using A. melanogenum MTGK.31 in a medium consisting of yeast extract, peptone, and glucose. The fermentation was done for 24, 48, and 72 hours. Total plate count and pH were measured after each fermentation period. The primary and secondary metabolites of G. verrucosa in each fermentation were observed. Antioxidant assay using the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) method was conducted, followed by total phenolic content using the Folin-Ciocalteu method. It was highlighted that yeast colony increased during the fermentation, while the pH level was decreasing. We found that the fermentation not only boosted some elements in primary metabolites, but also increased G. verrucosa bioactive groups. After 72 hours of fermentation, the G. verrucosa percent radical scavenging activity (%RSA) increased more than two times compared to the fresh G. verrucosa with a %RSA value of 16.09±6.57. Nevertheless, the highest total phenolic content of 5.62±0.00028 mg GAE/g extract was shown by G. verrucosa after 48 hours of fermentation.

No abstract

Gracilaria verrucosa is a red seaweed that has been widely utilized in the food andpharmaceutical industries due to its biological properties. The utilization of biologicalagents in obtaining certain bioactive compounds would confront unavoidable issues,particularly its bioactive sustainability. Hence, microbial fermentation has been reported as a practical approach to maintaining bioactive production and boosting its properties. Our study aimed to evaluate the potential of marine yeast Aureobasidium melanogenum MTGK.31 as a fermenting agent for G. verrucosa and characterize the seaweed metabolite profile and antioxidant activity after fermentation. The seaweed was fermented using A. melanogenum MTGK.31 in a medium consisting of yeast extract, peptone, and glucose. The fermentation was done for 24, 48, and 72 hours. Total plate count and pH were measured after each fermentation period. The primary and secondary metabolites of G. verrucosa in each fermentation were observed. Antioxidant assay using the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) method was conducted, followed by total phenolic content using the Folin-Ciocalteu method. It was highlighted that yeast colony increased during the fermentation, while the pH level was decreasing. We found that the fermentation not only boosted some elements in primary metabolites, but also increased G. verrucosa bioactive groups. After 72 hours of fermentation, the G. verrucosa percent radical scavenging activity (%RSA) increased more than two times compared to the fresh G. verrucosa with a %RSA value of 16.09±6.57. Nevertheless, the highest total phenolic content of 5.62±0.00028 mg GAE/g extract was shown by G. verrucosa after 48 hours of fermentation.