Browsing by Author "Aumasa T"

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    Starch digestibility of cooked rice as influenced by the addition of different tea types (Camellia sinensis): An in vitro study
    (Elsevier B.V., 2023-06-26) Apinanthanuwong G; Aumasa T; Ogawa Y; Singh J; Panpipat W; Donlao N
    The stability of tea catechin is influenced by various factors such as tea types, pH and digestive processes. The study aimed to investigate the effect of different tea types on the stability of tea catechin and their impact on starch digestibility and glycemic response to different types of cooked rice. Cooked rices were co-digested with green tea, oolong tea and black tea, and the catechin profiles were correlated with the inhibition of enzymatic digestion. The findings revealed that the green tea exhibited to be the most potent inhibitory effect on starch digestion. In addition, due to its highly porous structure, glutinous rice showed a higher starch hydrolysis rate and glycemic index than jasmine rice. The estimated glycemic index (eGI) of cooked jasmine rice co-digested with green, oolong, and black teas were 61.95 ± 1.07, 64.62 ± 1.12, and 67.14 ± 0.87, respectively, while eGI values of cooked glutinous rice were 77.55 ± 1.15, 79.98 ± 0.98, 81.45 ± 0.75, respectively. The findings indicates that epigallocatechin (EGC) achieves the highest stability. Overall, the results provided compelling evidence that tea types and rice structure affect the regulation of starch digestion and eGI of cooked rice.
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    The role of herbal teas in reducing the starch digestibility of cooked rice (Oryza sativa L.): An in vitro co-digestion study
    (Elsevier GmbH on behalf of Society of Nutrition and Food Science e.V, 2023-11-01) Aumasa T; Ogawa Y; Singh J; Panpipat W; Donlao N
    Herbal teas are well known for their antidiabetic effects due to the abundance of phenolic acids, flavonoids, and tannins. An in vitro co-digestion test was conducted to observe influence of herbal teas (HTs) i.e., beal fruit (BA), mulberry leaf (MB), gymnema leaf (GM), and chrysanthemum flower (CS) on starch digestibility of cooked rice and to elucidate correlation analysis of phytochemicals and their antioxidant activities during in vitro starch hydrolysis (SH). HTs prepared from GM and MB showed highest reduction of SH, kinetic constant and estimated glycemic index (eGI) of cooked rice, followed by BA and CS. Besides, MB and GM teas decreased the eGI of cooked rice up to 15%, followed by BA and CS teas, respectively. Phytochemicals and their antioxidant activities were positively correlated to SH, with both parameters displaying a higher decrease in intestinal phase when compared to gastric phase during in vitro co-digestion. These results indicate a strong interaction among phytochemicals and α-amylase in influencing glycaemic parameters. Thus, HTs has the potential to provide functional health benefits in lowering postprandrial hyperglycemia.