Starch Hydrolysis, Polyphenol Contents, and In Vitro Alpha Amylase Inhibitory Properties of Some Nigerian Foods As Affected by Cooking

Abstract

The effect of cooking on starch hydrolysis, polyphenol contents, and in vitro α-amylase inhibitory properties of mushrooms (two varieties Russula virescens and Auricularia auricula-judae), sweet potato (Ipomea batatas), and potato (Solanum tuberosum) was investigated. The total, resistant, and digestible starch contents of the raw and cooked food samples (FS) ranged from 6.4 to 64.9; 0 to 10.1; and 6.4 to 62.7 g/100 g, respectively, while their percentages of starch digestibility (DS values expressed as percentages of total starch hydrolyzed) ranged from 45.99 to 100. Raw and boiled unpeeled potato, raw and boiled peeled potato, raw A. auricula-judae, and sweet potato showed mild to high α-amylase inhibition (over a range of concentration of 10–50 mg/mL), which was lower than that of acarbose (that had 69% inhibition of α-amylase over a range of concentration of 2–10 mg/mL), unlike raw R. virescens, boiled A. auricula-judae, and boiled sweet potatoes that activated α-amylase and boiled R. virescens that gave 0% inhibition. The FS contained flavonoids and phenols in addition. The significant negative correlation (r = −0.55; P = 0.05) between the α-amylase inhibitory properties of the raw and cooked FS versus their SD indicates that the α-amylase inhibitors in these FS also influenced the digestibility of their starches. In addition, the significant positive correlation between the α-amylase inhibitory properties of the raw and cooked FS versus their resistant starch (RS) (r = 0.59; P = 0.01) contents indicates that the RS constituents of these FS contributed to their α-amylase inhibitory properties. The study showed the usefulness of boiled unpeeled potato, boiled potato peeled, and raw sweet potato as functional foods for people with type 2 diabetes.

PENGARUH TINGKAT SUBSTITUSI JAGUNG DENGAN UBI JALAR (Ipomoea batatas L.) KUKUS TERHADAP KUALITAS FISIK PELET RANSUM

“…Sumber utama energi dari ubi jalar adalah pati, sekaligus potensial sebagai perekat dan disintegran pelet. Pati terdapat sebanyak 58-76% dari bahan kering ubi jalar (Iheagwara, 2013) Dibanding pada biji-bijian, pati ubi jalar mentah lebih resisten terhadap aksi enzim percernaan seperti alfa-amilase (Saidu et al, 2017). Infiltrasi enzim akan mudah saat granula pati pecah akibat proses pemeletan atau pemasakan.…”

Organoleptic, hypoglycaemic, and in vitro starch digestion effects of formulated Melon Manis Terengganu peel powder

“…On the other hand, consumption of diet with high RDS level can stimulate a rapid hyperglycaemic response followed by glucose-induced insulin secretion from pancreatic β-cells (Chusak et al, 2018). Study stated that RS is a vital index for starch digestibility measurement which influences the GI (Saidu et al, 2017). Values are mean (standard deviation) (n = 3).…”