Hydrothermal treatments of two cowpea (Vigna unguiculata L. Walp) varieties: effect of micronisation on physicochemical and structural characteristics

Abstract

The effects of a hydrothermal treatment consisting of tempering (to 41% moisture) and heating to 153 • C (micronisation) on the structural and physicochemical characteristics of two cowpea varieties were studied. The untreated varieties had similar cooking times, although cooked Bechuana white cowpeas were significantly (P ≤ 0.05) softer and had a higher incidence of splitting than Var. 462 cowpeas. This may be due in part to differences in cotyledon structure affecting water uptake during cooking. The hydrothermal treatment changed the physical structure and chemical properties of the cowpea seeds. This led to significant (P ≤ 0.05) reductions in the cooking time of micronised Bechuana white and Var. 462 cowpeas, by 47 and 36% respectively, as compared with control samples. Micronisation caused physical fissuring of the seed coat and cotyledon and significantly (P ≤ 0.05) reduced the bulk density of treated seeds. These changes in the physical structure significantly (P ≤ 0.05) improved the initial water uptake during soaking and cooking, increased the enzyme-susceptible starch and reduced the protein solubility and hydration capacity of the cowpea seeds. Cooked (60 min) micronised cowpeas also had significantly (P ≤ 0.05) more splits and a significantly (P ≤ 0.05) softer texture than control samples.

Effect of High-Temperature Short-Time ‘Micronization’ of Grains on Product Quality and Cooking Characteristics

“…462 and Bechuana white) was explored by Mwangwela et al [32]. The cowpeas were micronized using a table-top micronizer in a single layer for 6 min to a final surface temperature of 153°C.…”

Hydration properties of different varieties of Canadian field peas (Pisum sativum) from different locations

“…In other studies, it has been reported that seeds might crack and become tough with improved absorption, but might also suffer higher leaching losses, if were heated to a high temperature (above 140°C) using an infrared treatment (Abdul-Kadir, Bargman, & Rupnow, 1990;Fasina, Tyler, Pickard, Zheng, & Wang, 2001;Mwangwela, Waniska, & Minnaar, 2006). Variations in hydration and dehydration of soybean and safflower have been shown to be a function of relative humidity (Vijay, Dadlani, & Nagarajan, 2009).…”

Effect of micronization of maize grains on shelf-life of flour

“…One of the ways to minimize these changes is through adopting high‐temperature short time processing techniques (HTST). In the recent past, micronization, an HTST technique that utilizes near‐infrared (NIR) rays has been employed to process cereals and legumes, such as lentils, cowpeas, peas, beans, sorghum, barley, wheat, maize, and rice bran to shorten the cooking time, to improve nutritional value, as well as to inactivate enzymes and anti‐nutritional factors (Andrejko, Rydzak, Oelaska‐Grzywna, Goÿdziewska, & Kobus, ; Arntfield et al, ; Cruzy Celis, Rooney, & Mcdonough, ; Deepa & Hebbar, ; Emami, Meda, Pickard, & Tyler, ; Fasina, Tyler, Pickard, & Zheng et al, , Fasina, Tyler, Pickard, Zheng, & Wang, ; Mwangwela, Waniska, & Minnaar, ; Yilmaz, Tuncel, & Kocabiyik, ; Žilić et al, ). Research reports available on micronization of maize grains mainly focused on evaluating the effect of IR processing on nutritional properties, antioxidant activity and on fromation of maillard reaction products (Žilić et al, ; Žilić et al, ).…”