PROPIEDADES DE DIGESTIÓN DE ALMIDONES NATIVOS Y MODIFICADOS DE PLÁTANO Y MANGO

Abstract

The digestion properties of starch have been classified on the basis of the amount of glucose released during the digestion: rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS). SDS and RS have beneficial physiological effects on the health of people that eats them. Due to this, it has searched different strategies to enrich these properties in commercial starches. The present work analyzed two strategies to increase the SDS and RS from no conventional sources of starch: banana and mango. It was used a chemical modification (acid hydrolysis) and enzymatic modification (debranching), and the products were physicochemical, morphological and structural characterized to explain the digestion properties. Native banana and mango starches, without gelatinization, presented low SDS content (5.06 – 18.00 %) and high RS content (86.40 – 63.42 %). Native banana starch, after gelatinization, presented higher SDS content (15.50%) in comparison with mango starch (10.60%). This is due to the molecular size distribution of amylopectin, banana starch showed a higher percentage of chains B1, B2 and B3. The acid hydrolysis had no effect on the SDS property for mango starch, whilst banana starch generated an increase from 5.06 % to 35.4 %, reached at 50 % of acid hydrolysis. On the other hand, RS increased from 50 % acid hydrolysis from 16.24% (7 days hydrolysis) to 21.9% (15 days of hydrolysis). Banana and mango lintners at 15 days of hydrolysis were made of chains with a single branch with a degree of polymerization (DP = 27-28) and by linear chains (DP=16-17). Native banana and mango starches presented a C-type X-ray diffraction pattern, which after the modification with acid hydrolysis was transformed to Atype pattern. Peak temperature of gelatinization in both starches increased from 7 days of acid hydrolysis. The modification by debranching increased the SDS content in mango starch from 10.60% to 26.5%, this was reached at 8 h of reaction (83% debranching), whilst banana starch increased the SDS content from 15.50% to 19.15%, this reached at 4 h of reaction (67% debranching). The debranching of mango starch increased RS content from 2.94% to 22.7%, at 24 h of reaction (100% debranching), and the debranching of banana starch increased RS content from 3.40 to 44.03%, at 24 h of reaction (100% debranching). Peak temperature of gelatinization of debranched starches increased compared with native starches, there was no change in the enthalpy of gelatinization. The debranched starches had higher thermal stability.