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

Abstract

Wheat flour replacement from 22.5% up to 45% by incorporation of ternary blends of teff (T), 25 green pea (GP) and buckwheat (BW) flours provided technologically viable and acceptable sensory rated 26 multigrain breads with superior nutritional value compared to the 100% wheat flour (WT) counterparts. 27Blended breads exhibited superior nutritional composition, larger amounts of bioaccessible polyphenols, 28 higher anti-radical activity, and lower and slower starch digestibility. Simultaneous lower rapidly digestible 29 starch (57.1%) and higher slowly digestible starch (12.9%) and resistant starch (2.8%) contents (g per 100 g 30 fresh bread), considered suitable nutritional trends for dietary starch fractions, were met by the blend 31 formulated 7.5% T, 15% GP, 15% BK. The associated mixture that replaced 37.5% WT, showed a rather 32 lower extent and slower rate of starch hydrolysis with medium-low values for C∞, and H90, and lowest k, and 33 intermediate expected Glycaemic Index (86). All multigrain breads can be labelled as source of dietary fibre 34 (≥3 g dietary fibre/100 g bread). A slow release and absorption of glucose may be generated in a food matrix according to the 56 processing conditions and surrounding ingredients (Lehmann & Robin, 2007), encompassing beneficial 57 effects in the management of diabetes and hyperlipidemia (Jenkins, 2007). Native cereal starches are ideal 58 sources of slowly digestible starch (SDS) (>50%), and the slow progressive digestion property is realized by 59 a layer-by-layer inside-outside (radial) digestion process (Zhang, Ao, & Hamaker., 2006a). Mechanical and 60 thermal treatments change the structure and digestibility of starch. Thermal treatments such as the cooking 61 process completely destroys the semicrystalline structure of native starch granules and causes the loss of 62 SDS and resistant starch (RS) and increases rapid digestible starch (RDS) (Zhang, Venkatachalam, & 63 Hamaker, 2006b). In cereal products, the starch gelatinisation extent, which is mainly controlled by the 64 moisture level and the cooking time and temperature influences the formation of SDS (Englyst, Vinory, 65 Englyst, & Lang, 2003). 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. 72 4 As a consequence, a reduction of the extent of starch gelatinisation takes place (Englyst et al., 1992). 73Fu...

Significance of thermal transitions on starch digestibility and firming kinetics of restricted water mixed flour bread matrices

“…Levels of wheat flour replacement were chosen after performing preliminary trials to set the range of non-wheat flours to be incorporated in associated blends to the formulations in such a way that significant enhancement of bread nutritional properties was achieved without notable deterioration of sensory attributes (Collar et al, 2014). The model resulted in eight randomized runs in 1 block.…”

“…A 3 digit bread sample code was set referring to low (0) ang high (1) wheat flour replacement by T (1st digit), GP (2nd digit), and BW (3rd digit) flours in sample formulation, as it follows: 0 1 0, 0 0 1, 0 1 1, 0 0 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0. Blended flours, water, commercial compressed yeast, salt, margarine, sugar, commercial sour dough, milk powder, Novamyl 10000, and calcium propionate were mixed, and used to make control and blended breads according to the quantitative formulations and breadmaking procedure described earlier (Collar et al, 2014). Bread samples were stored for 1, 3, 6, and 8 days to describe firming kinetics.…”

“…The chemical and nutritional composition of control and blended breads was fully determined in a previous paper (Collar et al, 2014), from where some selected bread characteristics are compiled in Table 1 In vitro starch hydrolysis kinetics and relevant starch fractions in freeze-dried and ground fresh blended breads was determined following the AACC (2005) method 32-40, adapted by Angioloni and Collar (2011) as previously described (Collar et al, 2014). Rapidly Digestible Starch (RDS) and Slowly Digestible Starch (SDS) were measured after incubation for 20 min and 120 min, respectively (Englyst, Vinory, Englyst, & Lang, 2003).…”

“…High wheat flour replacement by non-gluten forming flours from cereals, pseudocereals and legumes, particularly associated mixtures of teff, buckwheat and green pea have proven to provide technologically viable and acceptable sensory rated multigrain breads with superior nutritional value compared to the 100% wheat flour counterparts (Collar, Jiménez, Conte, & Fadda, 2014). Blended flours of different starch nature are expected to modify the mechanism of water mobility in bread crumb, and concomitantly its thermal properties during gelatinization and ageing due to water restrictions for swelling, gelatinization and starch hydrolysis.…”

Chemical characterization, texture and consumer acceptability of yogurts supplemented with quinoa flour

“…Pseudocereals are healthy and nutritive foods which provide vectors for diversification and innovation (Collar et al, 2014). Quinoa, (Chenopodium quinoa Willd) a pseudocereal crop native to the Andes, has been recognized as a nutritious grain worldwide, due to both the relatively high nutritional value (compared to staple cereals) as a source of unsaturated fatty acids, vitamins, minerals and bioactive compounds, and the quality of its proteins as regards its essential amino acid content (Graf et al, 2015).…”