Assessment of nutritional composition of barley genotypes under late sown irrigated condition

Introduction

Barley (Hordeum vulgare L.) is a major cereal crop grown across diverse agro-ecological regions of the world and is recognized for its stable productivity and nutritional value. Traditionally utilized as livestock feed and for malting industries, barley has recently attracted attention because of its nutritional value and health benefits. The grain contains appreciable levels of total protein, typically varying between 11 and 14 per cent depending on genetic makeup and environmental influences, thereby contributing significantly to plantbased protein intake in cereal diets (Baik and Ullrich, 2008) [2] . Barley is a nutritionally important cereal grain composed predominantly of carbohydrates and characterized by a relatively low fat content. In addition, it contains significant amounts of protein, essential minerals, and vitamins, particularly vitamin E. It is also a rich source of dietary fiber and bioactive compounds, especially antioxidants such as polyphenols, which contribute to its overall nutritional and health-promoting value (Das et al., 2016) [6] . Barley also contains relatively low levels of total fat, generally less than 3 per cent, predominantly consisting of unsaturated fatty acids that enhance its dietary value while supporting grain storage stability (Newman and Newman, 2006) [13] . In addition to these macronutrients, barley grains supply essential trace elements such as zinc and iron, which are vital for metabolic processes, immune function and oxygen transport, and play an important role in addressing micronutrient malnutrition (Graham et al., 2007) [7] . The crop exhibits significant nutritional value along with functional properties that contribute to health promotion (Cook, 2013; Idehen et al., 2017) [4,10] . It is well established that diets rich in β-glucan enhance immune function and offer protection against conditions such as hypertension, stroke, cardiovascular diseases, and type 2 diabetes (Maheshwari et al., 2019; Tosh and Bordenave, 2020) [12,16] . Given the widespread occurrence of zinc and iron deficiencies in many developing regions, characterization of barley genotypes for these nutritional traits is crucial. Hence, systematic evaluation of Crude protein, total sugar, fiber, fat, zinc and iron content under late sown irrigated condition is instrumental in identifying nutritionally superior genotypes and facilitating breeding efforts aimed at grain quality enhancement and biofortification.

Materials and Methods

36 barley genotypes were obtained from Indian Institute of Wheat and Barley Research, Karnal, Haryana. The experiment was conducted using a Randomized Block Design (RBD) with two replications under late sown irrigated condition.

Chemical analysis

Crude protein content was determined by the Micro-Kjeldahl method (A.O.A.C., 2000). A 200 mg defatted sample was digested with concentrated sulphuric acid in the presence of a catalyst mixture until a clear solution was obtained. The digest was diluted, made alkaline with sodium hydroxide, and the liberated ammonia was distilled and trapped in boric acid solution containing mixed indicator.

The distillate was titrated against standard 0.02 N hydrochloric acid. Nitrogen content was calculated from the titration value, and crude protein percentage was obtained by multiplying nitrogen percentage with a conversion factor of 5.83. Total sugar was determined using the phenol-sulphuric acid method. Barley grain sample (0.5 g) was extracted with 80 per cent ethanol, and an aliquot of the extract was reacted with phenol and concentrated sulphuric acid. After colour development, absorbance was measured at 490 nm. Total sugar content was quantified using a glucose standard curve and expressed as percentage. Crude fiber content was determined according to AOAC (2000) [1] by acid-alkali digestion method. A 2 g fat-free dried sample was sequentially digested with 1.25 per cent sulphuric acid and 1.25 per cent sodium hydroxide under controlled boiling conditions. The residue was filtered, thoroughly washed, dried to constant weight at 100°C and then ashed at 550°C in a muffle furnace. Crude fiber percentage was calculated from the loss in weight after ashing and expressed on sample weight basis. Crude fat content was determined by Soxhlet extraction method using petroleum ether (40-60°C) as solvent (A.O.A.C., 2000). Approximately 5 g of powdered sample was extracted in a Soxhlet apparatus until complete siphoning cycles were achieved. The solvent was evaporated and the flask containing extracted fat was dried to constant weight. Crude fat percentage was calculated from the difference in weight of the flask before and after extraction and expressed on sample weight basis. Zinc content was estimated using Atomic Absorption Spectrophotometry (AAS). One gram of finely powdered barley seed sample was digested with a nitric acid and perchloric acid mixture (5:1) and heated until complete digestion was achieved. The digest was cooled, diluted to a known volume with distilled water and filtered. The filtrate was analyzed for zinc concentration using an atomic absorption spectrophotometer and results were expressed as mg per 100 g of sample.

Iron content was determined by Atomic Absorption Spectrophotometry (AAS). One gram of finely powdered barley seed sample was digested with a nitric acid and perchloric acid mixture (5:1) until a clear solution was obtained. The digest was cooled, diluted to a known volume with distilled water and filtered. The filtrate was analyzed for iron concentration using an atomic absorption spectrophotometer and the results were expressed as mg per 100 g of sample.

Results and Discussion

The chemical composition of different barley genotypes is presented in table 2.

The crude protein content of barley genotypes ranged from 9.05% to 13.32%, with an overall mean of 11.41%. The highest protein concentration was recorded in BH 902 (13.32%), followed by RD 2624 (12.86%), DWRUB 64 (12.72%), and BHS 352 (12.57%). Lower protein levels were observed in DWRUB 52 (9.05%) and DWR 28 (9.46%). The results indicate that barley grains possess appreciable protein content, with certain genotypes exhibiting relatively higher protein concentration. These findings are accordance with the Yadav et al (2000) [20] , Dabas et al. (2005) [5] , Singh (2005) [15] , Saharan (2009) [14] . [18] . Crude fiber content varied from 3.13% to 5.45%, with a mean of 4.33%. The highest fiber content was recorded in BHS 352 (5.45%), followed by K 603 (5.40%), NB [17] , Saharan (2009) [14] , Biel and Jacyno (2013) [3] . Crude fat content ranged from 1.31% to 2.18%, with an overall mean of 1.86%. lower fat levels were recorded in DWRB 160 (1.31%), HBL 276 (1.39%), and BHS 400 (1.47%). Similar results were obtained by Singh (2005) [15] , Varsha et al. (2006) [17] . Zinc content ranged from 1.48 to [9] , Kaur et al.

(2024) [11] , Wotango et al. (2024) [19] , Yiblet et al. (2024) [21] . Overall, the results demonstrate that barley grains possess substantial levels of protein, sugars, fiber, fat, zinc, and iron, indicating their nutritionally rich compositional profile and significance of nutritional characteristics is growing in plant breeding initiatives focused on enhancing crop quality. In barley, differences in protein, fiber, and essential micronutrients such as zinc and iron provide opportunities for selection and genetic enhancement. Recognizing genotypes that are high in nutrients can help in creating biofortified varieties, thus improving both productivity and nutritional security.

Conclusion

The present investigation evaluated the nutritional composition of barley genotypes in terms of crude protein, total sugar, crude fiber, crude fat, zinc, and iron content. The results indicated that barley grains possess appreciable levels of both macronutrients and micronutrients, confirming their high nutritional value. Higher protein content was observed in genotypes such as BH 902 and RD 2624, while RD 2668 recorded higher total sugar content. The genotype BHS 352 exhibited relatively higher crude fiber, whereas DWRB 160 and HBL 276 showed comparatively lower crude fat content. Among micronutrients, JB 58 recorded higher zinc content and NB 1 exhibited higher iron concentration. Overall, the variation among genotypes reflects distinct nutritional profiles, highlighting the potential of barley as a nutrient-rich cereal crop.

Acknowledgment

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