Status of phytic acid content in Indian barley (Hordeum vulgare L) varieties and its correlation with other grain parameters

Phytic acid, myo-inositol 1,2,3,4,5,6-hexakisphosphate (InsP6), is the major form of stored phosphate in food grains and reported to contain 50-80% of total phosphorus in the grain (Gupta et al., 2015; Silva et al., 2021). Besides binding the phosphorus, phytic acid is also known as chelator of cations like Fe2+, Zn2+, Mg2+, Ca2+ and K+ (Liu et al. 2005). Barley grains contain appreciable amount of minerals, but their availability is low because of the formation of insoluble complexes with phytate, a salt of phytic acid, which is also one of the main inhibitors for iron and zinc absorption in humans (Ockenden et al., 2004). Therefore, phytic acid is also regarded as ‘anti-nutritional’ factor as it reduces the bioavailability of important minerals. Although the direct use of barley as food is very limited, but the proper availability of minerals is very important for balanced nutrition specially for poor and underdeveloped populations. The major portion of barley production (60-70%) goes as animal feed and there also poor bioavailability of minerals may lead to under nutrition and thereby its consequences in animals as well. Further, chelated phosphorus ends up in the faecal matter led environmental pollution. Around 25-30% barley goes for malt industry. During malt production also different energetic and biosynthetic processes require phosphorus and other minerals (Lee, 1990). Phytic acid also show the ability to form complexes with proteins affecting their solubility and ultimately their degradation into smaller peptides. So, lower values of phytic acid and/or higher activity of phytase enzyme (which breaks down phytic acid into inositol and phosphates) are highly desirable. After barley malting, larger proportion of malt is used for brewing where yeasts do the fermentation of wort (malt extract). For fermentation as well, besides various other nutrients, sufficient availability of zinc and magnesium has been shown to improve the fermentation efficiency (Lee 1990; Rimsten et al., 2002; Dai et al., 2007; Edney et al., 2011). Therefore, irrespective of the end use of barley, be it feed, malt or food, lower levels of phytic acid is one of the important and desirable trait. This study was conducted with two objectives; first to know the status of phytic acid in Indian barley varieties and second to see if any correlation of this parameter exists with other physical traits of barley grain.