Oat Bran Fermentation by Rye Sourdough

Abstract

Hydration of oat bran including fermentation by rye sourdough was studied. Three types of oat bran suspensions were prepared (a control, one with whole meal rye flour added, and one with rye starter added). The suspensions were incubated for 1, 2, 3 and 4 hr. β‐Glucan content and solubilities of protein and β‐glucan were analyzed. Viscosity of the supernatants of oat bran suspensions was determined. Neither the rye sourdough nor the rye flour alone had a significant effect on the total β‐glucan content of oat bran suspensions. However, the addition of rye, either as whole meal rye flour or as sourdough starter, markedly increased the solubility of β‐glucan and proteins and simultaneously decreased the viscosity of the water‐soluble fraction of oat bran suspension. This suggests that a hydrolysis of β‐glucan had occurred that could change the rheological properties of oat bran in baking and the physiological potential of oat bran in nutrition.

Optimization of ingredients and baking process for improved wholemeal oat bread quality

“…The reason for the partial degradation of b-glucan in oat bread may be the b-glucanase activity of the wheat flours. Several studies have shown that endogenous b-glucanase activity will decrease the content (Degutyte-Fomins et al, 2002;Ellis et al, 1997;Henry, Martin, & Stewart, 1989) and average molecular weight of barley b-glucan (Rimsten, 2003). Å man et al (2004) found that large particle size of the oat bran and short fermentation time limited the b-glucan degradation during baking.…”

“…Exceeding this amount of oat leads easily to tight, moist, and gummy breads. The effect of oat on dough properties and bread quality have been studied so far with addition of oat bran, flakes or flour from 10 to 25/100 g wheat flour (Degutyte-Fomins, Sontag-Strohm, & Salovaara, 2002;Krishnan, Chang, & Brown, 1987;Oomah, 1983;Zhang et al, 1998). In all these cases, breads with 10 g oat/100 g wheat flour had better loaf volume, crumb grain, and texture than breads with 15-25 g oat/100 g wheat flour.…”

In vitro measurements of luminal viscosity and glucose/maltose bioaccessibility for oat bran, instant oats, and steel cut oats

“…It is important to note that our current experimental design involves the use of oat grain samples that have been exposed to variable commercial processing techniques. Many researchers have demonstrated that commercial processing methods modify b-glucan quality, such as its molecular weight (Degutyte-Fomins et al, 2002;Wood, 1993;Zhang et al, 1998). In addition, the prepared oat-based meals underwent different preparation/cooking methods (Table 2) and also contained different quantities of starch and b-glucan in order of attaining a physiological response (in vitro) that is most representative of the typical serving of oats.…”

“…Processing of the whole oats changes the physical/structural (Miller & Fulcher, 2011) and chemical characteristics. Many researchers have demonstrated that commercial processing methods modify b-glucan quality (e.g., solubility and molecular weight) (Degutyte-Fomins, Sontag-Strohm, & Salovaara, 2002;Wood, 1993;Zhang, Doehlert, & Moore, 1998), bglucan quantity (Decker, Rose, & Stewart, 2014), and starch integrity (e.g., gelatinization) (Grandfeldt, Eliasson, & Bjorck, 2000;Lookhart, Albers, & Pomeranz, 1986;Ovando-Martinez, Whitney, Reuhs, Doehlert, & Simsek, 2013;Yiu, 1989). A recent systematic review by Tosh and Chu (Tosh & Chu, 2015) shows a wide range of glycemic indices, ranging between 40 and 88, for differently processed whole oat grains.…”

Viscosity of beta-glucan in oat products

“…Processes involving enzymatic breakdown of beta-glucan may affect the physical state of beta-glucan and reduce its viscosity (Mälkki and Virtanen 2001). Enzymatic breakdown of beta-glucan in processes, including breadmaking were shown in studies where enzyme active ingredients were used (Jaskari et al 1995, Degutyte-Fomins et al 2002. However, most of the clinical studies on oats and oat products have paid little attention to describing of the physical state of the beta-glucan.…”