Controlled differential hydration process with high retention of soluble solids (PHDC) for food grains

Abstract

The development of a new hydration process, called Controlled Differential Hydration (PHDC), thus removing the soluble solids losses that normally occur in conventional hydration processes. The need to hydrate the soybeans to a level compatible with the wet processing without loss of soluble solids leaching was the starting point for the development of the process, introducing a new concept, the effective volume (Veff). This hypothetical condition was first demonstrated on a laboratory scale, culminating in the construction of a pilot equipment called PHDC-Rotator, which in addition to moisturize the beans without soluble solids losses, resulted in increased bioavailability of isoflavones during simultaneous hydration and incubation, by the action of endogenous enzymes in the soybean optimized conditions of the hydration process (54 o C /15 rpm), promoting a large increase in the amount of aglycone. The overall conversion rate of glicossídicas isoflavones to aglucone was greater than 65% to leaching without water of hydration. The content of aglycone isoflavones increased from 10.23 µg.g-¹ in the raw material to 283.34 µg.g-1 in soybeans processed. The conventional heat treatment (120ºC, 1 kg.cm-2, 5 min) needed to achieve the nutritional and sensory characteristics, produced an additional hydrolysis of glucosides, representing an additional 14% increase aglycones. The entire process has allowed an overall increase of 28.9 times (molar basis) conversion of all forms of isoflavone glucosides to aglucone, particularly (S) -equol, precursor of daidzein and with minimal back diffusion or leaching into the water of hydration. The PHDC-Rotator showed a great potential to modify and / or preserving other nutritional and sensory characteristics of the grains during hydration, the enrichment of the grain minerals, vitamins and natural dyes, such as the preservation of anthocyanins black bean. In addition to the functional and economic aspects resulting from the high retention biocompounds the PHDC, the new allowed process that all soluble solids soy participate synergistically in diets in general (Cassidy et al., 2006), increasing substantially the availability or micronutrients amount of biomolecules and soya weight unit consumed, and thereby significantly reducing the amount of soybeans to be ingested to provide the functional benefits. In this sense, the development of PHDC represents incremental technological innovation of great importance for the production of functional convenience foods to particularly soy and other grains in general and has a great social significance , as it will allow the low-income population may have access to convenience products with high functional and nutritional content at low cost. (AU)