In‐vitro availability of starch in cereal products

Abstract

The in-vitro availability of starch in Heudebert breads and Lu biscuits was assessed.Starch digestibility increased in the order semi-sweet biscuits, muesli, wholemeal breads, white breads, French toast, extruded crispbread. The results confirm that manufacturing conditions play a determinant role in starch availability in vitro.The samples were ground to pass through a 0.5-mm screen; products with more than 7 % fat were defatted first. Reducing sugars, sucrose, starch and rate of hydrolysis of starch in vitro were determined by the method of Wong et a1 (1985).The results are given in Table 1. The reducing sugars content of biscuits varies between 6 and 119 g kg-'. The sucrose content of the analysed products varies between 0 (bread) and 254 g kg-' for the semi-sweet biscuit n.4.The proportion of the starch hydrolysed in 30 min is 4 % in the uncooked soluble starch (Merck No 1252), 2&44% in biscuits, 4&72% in the breads, crackers and French toast, and 86 % in the extruded crispbread. Wootton and Chaudhry (1980) also showed that the in-vitro availability of starch increased in the order of shortbread biscuits, sweet cookies, crackers and bread; the extent of starch gelatinisation is correlated with the availability of starch in vitro. Ross et a1 1987 showed that the rate of starch hydrolysis in vitro was similar in a water biscuit and wholemeal bread (74 and 76%, respectively), whereas in a shortbread biscuit starch was significantly less available, 58 % ( P < 0.001).Jenkins et a1 (1982a) observed a relatively low blood glucose response to biscuits, the glycaemic index of four kinds of sweet biscuit varying between 54 and 63 %; the authors attributed the low glycaemic index to the poor response to sucrose. It may also be due to the limited degree of gelatinisation of starch in biscuits and to the slowing down of gastric emptying by the fat. 499 J Sci Food Agric 0022-5142/89/$03.50

Prediction of Degradability of Starch by Gelatinization Enthalpy as Measured by Differential Scanning Calorimetry

“…Our results show that there is a relation between the degradation of starch and the gelatinization enthalpy measured by DSC. This is in agreement with Le Fruncois [25], who found that the rate of starch hydrolysis in vitro can be used for assessing the degree of gelatinization of starch in cereal products. Akingbula [26], howtrarchktarke 44 Nr.…”

Impact of ancient cereals, pseudocereals and legumes on starch hydrolysis and antiradical activity of technologically viable blended breads

“…In bread dough, although formation of resistant starch (RS3) may occur in the high 66 water-containing parts during cooling, a large portion of starch is gelatinised during cooking and induces a 67 rapid digestibility of starch (Bravo, Englyst, & Hudson, 1998). In extruded cooked cereal products such as 68 breakfast cereals, in addition to the thermal treatment, the high pressure and shear forces destroy the 69 starch granular structure and increase its gelatinisation extent, making it more available to amylolytic 70 enzymes (Le François, 1989). On the contrary, in pasta, a dense protein network is formed, which limits the 71 accessibility of α-amylase to the starch and restricts the diffusion of water molecules to the starch granules.…”

Effect of Specific Mechanical Energy on &lt;i&gt;In-Vitro&lt;/i&gt; Digestion and Physical Properties of Extruded Rice-Based Snacks

“…In an extrusion process, destruction of starch structure and gelatinization of starch are achieved by both thermal cooking and physical shearing [2] [34] [35]. In this study, higher SME indicated higher degree of mechanical Figure 1.…”

“…Several approaches have been developed to predict GI using in-vitro methods, which are economical, convenient, and more likely to produce objective results [5] [26] [35]. According to Englyst et al [37], starch can be classified to three categories based on digestibility: rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS).…”