[4-1600-A] Postharvest/Food Technology and Process Engineering (3)

[4-1600-A-07] In Vitro Release Characteristics of Sugars and Hydrolysis of Starch During Simulated Digestion of Saba banana at Different Maturity Stages

*Florencio, Jr. Collado Reginio^1,2, Wei Qin¹, Yukiharu Ogawa¹ (1. Graduate School of Horticulture, Chiba University(Japan), 2. Institute of Food Science and Technology, College of Agriculture and Food Science, University of the Philippines Los Baños(Philippines))

Keywords:maturity, starch digestibility, viscosity, sugars

Saba banana [Musa ‘saba’(Musa acuminata x Musa balbisiana)] is one of the most popular fruit crops in terms of production and trade in the Philippine food industry. It has a wide range of applications in the domestic market and is also known to offer great nutritional and health benefits. However, restriction of banana consumption as desserts or snacks is suggested as it also contains higher amounts of carbohydrates compared to other fruits. The determination of bioavailable carbohydrate in a given product is necessary to predict its effect on postprandial blood glucose response. Thus, this study was conducted to examine the changes in sugar and starch fractions of Saba banana during simulated in vitro gastrointestinal digestion. Five maturity stages of Saba banana were identified based on peel color index (1, all green; 2, green but turning yellow; 3, greenish yellow; 4, yellow with green tips; and 5, yellow with brown flecks). Unhomogenized cut and homogenized slurry samples representing intact tissue and structure-less states of Saba banana were obtained in each maturity stage and evaluated for starch hydrolysis rates. Physicochemical properties during maturation, and release characteristics of sugars (sucrose, fructose, and glucose) and viscosity of digesta during in vitro digestion were also determined. The decrease in total starch content was an indication that starch degradation occurred during ripening. More than 70% of resistant starch was degraded from unripe to overripe stage. During the course of digestion, a significant decrease in sucrose was observed whereas glucose and fructose contents increased concomitantly. The highest starch hydrolysis (%) for both homogenized and unhomogenized states was determined in unripe stages and a decreasing trend was observed as maturity advanced. The higher digesta viscosity values of ripe stages than unripe counterpart could influence its susceptibility to digestion by reducing the extent of mixing and the interaction with digestive enzymes. Additionally, comparing the two states, the unripe stages of homogenized slurry samples were found to have significantly higher percent starch hydrolysis and shorter digestion time than unhomogenized cut samples owing to the difference in structure. These results provide an understanding of the different factors that significantly impact starch digestibility during maturation of Saba banana.