Effect of Germination Process on the Chemical and Biological Active Compounds of Barley and Oat Grains

Abstract

In recent years, cereals especially barley and oat grains have attracted researches and commercial attention mainly due to their high contents of dietary fibers, βglucan and phenolic compounds with high antioxidant activates. Therefore, a preliminary study was carried out to estimate the components of raw barley and oat grains as well as, the effect of germination process on chemical composition and biological active compounds. The obtained results reveled that the germination process had a great role on the efficiency of chemical composition of selected cereal grains. A large number of negatively valued components in the grains such as crude fibers and starch contents of barley and oat decreased with prolonging the germination time process and the reduction of their contents due to the activity of αamylase enzymes during germination process which led to an increase in total sugars. Phytic acid decline with germination time increase. Otherwise, protein contents gradually increased with prolonging the germination period being 15.24 and 12.96% after three days for barley and four days for oat, respectively. Prolonging the germination time increased the minerals content of barley and oat grains and improved the bioavailability of essential minerals. Moreover, β-glucan contents declined with increasing the germination time process. Prolonging germination period increased total phenolic compounds, flavonoids contents and antioxidant activity, Catechin and pyrogallol were the major free phenolic compounds that existed in raw and germinated barley and oat grains. Nicotinic acid and Vit. B1 were the most abundant B complex vitamins in raw barley and oat grains and they highly increased during the germination period more than two folds recording 120.81 and 145.56 mg/100g & 335.21 and 441.62 mg/100g, respectively. Finally, it could be concluded that germination process had positive effects to improve the bioactive compounds contents as total phenolic and flavonoids compounds, antioxidant activity and an increase in bioavailability of essential minerals and a higher content of Vit. B complex of barley and oat grains.

Proceeding

“…Oat grains subjected to germination were analyzed for mineral content and the results are depicted in Table 1. * Corresponding author's email: rmeenuspolia697@gmail.com Magnesium content increased from 169.55 to 187.25 mg/100 g, phosphorus from 429.61 to 454.61 mg/100 g, calcium from 4.70 to 7.72 mg/100 g, and iron from 4.70 to 7.72 mg/100 g. Our results are consistent with the findings of Refai et al (2012) who reported higher values of magnesium, calcium, zinc, and iron content in oats and barley grain subjected to soaking and germination (48 and 72 h). Further, the functional properties of oats flour were also affected after germination: bulk density decreased from 0.76 to 0.38 g/mL, water absorption capacity from 68.80% to 108.28%, and oil absorption capacity from 186.33% to 199.92 %.…”

Changes in Total Phenolic Compounds and Antioxidant Activity During Domestic Processing of Some Cereal Grains

“…Donkor, et al (2012) reported that the radical scavenging activities of the phenolic extracts were between 13% and 73% for non-germinated and 14% and 53% for germinated of seven selected commercially important grains including wheat and sorghum. In contrary, Lo´pez-Amoro´s, et al (2006) found that peas and beans undergo a significant increase in antioxidant activity after germination, and El-Refai et al (2012) found also that the antioxidant activity was increased by increasing the germination period of barely and oats grains.…”

“…In fact, the germination process is also one of methods used to improve the functionality of oat seed protein (Kaukovirta-Norja, et al, 2004). Recently, El-Refai et al (2012) found that germination process had positive effect to improve the bioactive compounds content as total phenolic anf flavonoids of barely and oat grains. In general soaking period was reported to have pronounced effects on the vitamin levels and anti-nutritional factors present in natural foods (Fadahunsi, 2009).…”

The role of germination in changes in bioactive properties, polyphenols and biogenic elements of raw and germinated barley (Hordeum vulgare) parts

“…EL‐Refai et al . (2012) determined 0.99–5.11 gallic acid, 30.98–40.17 catechin 43.05–189.21 pyrogallol, 2.88–23.50 clorogenic acid, 0.72–2.46 ferulic, 1.02–6.38 mg/100 g syringic in raw and germination barley grain. It has been reported that after 120 h of germination, the amounts of phenolic compounds in oats increased more than 4‐fold compared to the control (Tian et al ., 2010).…”