Changes in the concentration of carbohydrates during the soaking of soybeans for tempe production

Abstract

Soybeans were soaked for 24h in tap water at 30°C in preparation for tempe fermentation. Soaking was conducted under conditions that give a microbial fermentation, and in the presence of antibiotics where microbial growth was inhibited. Sucrose, stachyose and raffinose were the main di-and oligosaccharides in the beans, and their concentrations decreased by 84, 65 and SO%, respectively, during soaking. Glucose, fructose and galactose were found in the soak-water along with lesser amounts of sucrose, melibiose, raffinose and stachyose. Glucose was the main substrate for microbial growth in the soak-water. The concentrations of mono-, diand oligosaccharides in the beans and in the soak-water were determined by the activity of invertases and a-galactosidases endogenous to the beans, diffusion of the sugars into and out of the bean, and the species of micro-organism growing in the soak-water. KeywordsFermentation, soybean microbial metabolism, oligosaccharide breakdown.

Changes in the concentration of organic acids during the soaking of soybeans for tempe production

“…The microbial cells were cultured and inoculated into the soak-water to give an initial population of approximately 104 c.f.u. ml-' as described in Mulyowidarso et al (1991). The beans were soaked for 24 h at 30°C.…”

“…Bean samples (10 g) were homogenized, defatted and extracted with distilled water as described by Mulyowidarso et al (1991) for total water-soluble carbohydrate. The extracts were treated with 0.1% trifluoroacetic acid to precipitate protein.…”

“…Samples of soak-water were collected and processed by ultrafiltration and passage through Sep-Pak C-18 cartridges before analysis by HPLC as described by Mulyowidarso et al (1991).…”

Anti-Diarrhoeal Aspects of Fermented Soya Beans

“…Carbohydrates in soya beans comprise mainly cell wall polysaccharides and the small sugars fructose, raffinose and stachyose. These small sugars are removed during soaking, cooking and fermentation of the soya beans (Egounlety & Aworh, 2003;Mulyowidarso et al, 1991). The insoluble cell wall polysaccharides, such as pectin, cellulose and hemicellulose www.intechopen.com are (partly) degraded during fermentation by the enzymes of the mould which leads to their enhanced water-solubility (Kiers et al, 2000).…”

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“…Although antinutritive factors such as alkaloids, phytates, saponins, cyanogenic glycosides, trypsin inhibitors, oxalates and tanins are constituents of soybean and tigernut; preprocessing steps such as soaking and dehulling (Mulyowidarso et al, 1991;Gibson andRoberfroid, 1995, Mumba et al, 2004;Adejuyitan et al, 2009;Ade-Omowaye et al, 2009;Adekanmi et al, 2009;Chukwuma et al, 2010;Nwaoguikpe, 2010;Sanchez-Zapata et al, 2012, Djomdi et al, 2013Kumari et al, 2014), sprouting (Adekanmi et al 2009, Kumari et al 2014, blanching (Adekanmi et al, 2009;Sanchez-Zapata et al, 2012, Ari et al, 2012 and roasting (Adekanmi et al, 2009;Sanchez-Zapata et al, 2012) can significantly reduce these antinutritive factors thus enhancing nutritional compositions and physicochemical properties of its flour. The purpose of this work is to develop and optimize a tigernut-based spread with good sensory attributes which is acceptable, but contains added sugar (≤ 6%) and iodated salt (50ppm,≤ 0.3%) for therapeutic use.…”