Physicochemical characteristics and resistant starch of different varieties of banana from Taiwan

Abstract

Banana contains high levels of resistant starch (RSC), which resists digestion. Taiwan is a major producer of banana; however, little work has been reported on their specific characteristics. This study was conducted to investigate the characteristics and RSC of ripe and unripe Taiwanese bananas. The characteristics and RSC significantly differed between varieties and ripening stages. The hardness, L*, pH values, swelling power, total starch, and amylose contents of unripe bananas were significantly higher than ripe bananas, while the starch content depended on the variety and ripening stage. Therefore, Taiwanese bananas could be useful RS source for manufacturing functional foods.

Physical and Chemical Properties of Different Varieties of Taiwanese Bananas and Their Application in Banana Flat-Rice Noodles

“…The amylose contents of the ripe and unripe bananas were determined using a previously published method with slight modifications. [11] The banana sample (90 mg), 1 mL of 95% ethanol, and 9 mL of 1 N NaOH were mixed and incubated at 30°C for 24 h. The volume was adjusted to 100 mL by adding distilled water. Next, 1 mL of 1 N acetic acid and 2 mL of iodine solution (0.2% I 2 in 2% KI) were added to a 5 mL aliquot of this adjusted solution.…”

“…The total starch contents of the ripe and unripe bananas were determined using a YSI 7100 Biochemistry Analyzer (YSI Incorporated, Yellow Springs, OH, USA) according to a previously published method with some modifications. [11] This method was based on an immobilized enzyme biosensor that measured the glucose levels after hydrolysis. A 0.5 g sample of banana powder was weighed and transferred to a 100 mL volumetric flask, and 25 mL of distilled water was added.…”

“…The RSC was determined by following a previously described method. [11] Banana powder samples (0.4 g, dry basis) were weighed in centrifuge tubes with 20 mL of phosphate buffer (pH 6.0 [55.6 mM]), and 0.16 g of α-amylase (A-3176, Sigma-Aldrich, St. Louis, MO, USA) was added to each tube. The mixture was incubated at 37°C for 16 h. The sample was adjusted to a pH of 4.5 using phosphoric acid solution (2 mL/100 mL) and 0.4 mL of amyloglucosidase (A-7095, Sigma-Aldrich, St. Louis, MO, USA) was added, followed by the incubation of the solution at 60°C for 30 min.…”

“…The procedure used to prepare banana flat-rice noodles was based on a method proposed in the literature with slight modifications. [11] The TCS 17 rice sample was removed from the refrigerator maintained at 7°C and placed in a stainless-steel container at room temperature for 2 h. Next, 200 g of TCS 17 was weighed in a stainless-steel basin, and 200 g of distilled water was added to facilitate soaking at room temperature for 2 h. A grinder (Fe-05, Yung Soon Lih Food Machine Co., Ltd. Taichung, Taiwan) was used to grind TCS 17 for 5 min. The ground material was then poured into a stainless-steel basin, which was heated using a thermostatic water bath (BH-230D; Yihdder Company, New Taipei City, Taiwan) maintained at 85°C for 18 min to stimulate gelatinization.…”

“…Therefore, it has generated considerable interest in the food processing industry because of its ability to reduce the risk of colon cancer, rectal cancer, coronary heart disease, diabetes, and other diseases. [10] Unripe bananas are rich in RS II, [11] and owing to their low digestibility, substantial research efforts have been directed toward investigating their use as a raw material for food processing. During the ripening process, starch is converted into sucrose, glucose, and fructose via enzymolysis.…”