The processing was done according to the procedure given by Hussain and Kaul (2019). The grains were cleaned manually by removing the diseased grains and foreign materials, washed thoroughly under tap water to remove dust and then, dried in shade. The dried grains of buckwheat and barley were coarse ground in a laboratory mill (Philips, Model: HL 1632). The ground grains were sieved through ISI Mesh No. 20 (0.833 mm) for medium fractions (grits) and stored in air tight containers till further use. The washed, destoned and dried apricots were converted into powder and packet in air tight containers. The method of Kikafunda et al. (2010) was followed for developing multigrain porridge mix. Grits of buckwheat and barley and apricot powder were blended separately in different ratios with each other for making different formulations as F₁(100:0:0::BWG:BG:AP), F₂(0:100:0::BWG:BG:AP), F₃(80:10:10::BWG:BG:AP), F₄(70:20:10::BWG:BG:AP), F₅(60:30:10::BWG:BG:AP) and F₆(50:40:10::BWG:BG:AP).

The blended mixture of each treatment was packed in aluminium laminated pouches and stored for the shelf-life study of 150 days at ambient temperature (28 ± 3 ºC) and moisture content (12 ± 0.8%). The samples were analysed for various chemical constituents at an interval of 30 days following the standard procedures.

The porridge mixes with formulations 100: 0:0::BWG:BG:AP, 0:100:0::BWG:BG:AP, 80: 10: 10::BWG:BG:AP, 70:20:10::BWG:BG:AP, 60: 30:10:: BWG:BG:AP and 50:40:10::BWG:BG:AP were analyzed after the storage at 30 days interval period.

Moisture, protein, ash and fat contents were measured according to AOAC methods (2002). The carbohydrate content was calculated by difference method by subtracting the sum of moisture, fat, protein and ash contents from 100. The antioxidant activity was determined by DPPH (1,1, diphenyl-2picryihydrazyl) scavenging activity (Brand-Williams et al., 2002). All the experiments were performed in triplicates. Data collected from aforesaid experiments were subjected to ANOVA (statistical analysis) with the help of factorial completely randomized design (Gomez and Gomez, 2010) and using the OP Stat software package.

According to the results presented in Table 2, the incorporation of barley grits led to the increase in mean protein content of porridge mix significantly from 7.39 % to 10.45 % having maximum in F₆ and minimum in F₁, respectively. The increase in protein content of the multigrain porridge is clearly attributed to the high protein content of barley than that of buckwheat. Pelembe et al. (2002) reported increase in protein content of the extrudates with increase in the amount of cowpea in the sorghum-cowpea instant porridge. Similar increase in protein content with the increase in walnut powder in complementary food formulated from sorghum, walnut and ginger was reported by Adebayo-Oyetoro et al. (2013). As in evident from the data, that during 150 days of storage period, the protein content of porridge mix decreased from the initial levels of 9.81 % to 7.15 %. This observation could be due to hydrolysis of protein molecules during storage. These findings are in line with that of Butt et al. (2008) and Leelavati et al. (1984) while storing wheat flour. Upadhyay (1994) also observed similar results in suji stored in different packaging materials.

Table 3 delineates the effect of treatment and storage periods on crude fat content of multigrain porridge mix. The lowest mean fat content of 1.15 % was recorded in formulation F₂ followed by formulations F₆ and F₅ having fat contents of 1.72 % and 1.86 %, respectively. The highest mean fat content of 2.56 % was recorded in control F₁ (100:0:0::BWG:BG:AP). Kawka et al. (1999) reported increase in crude fat content of bread with the substitution of barley flakes in wheat flour and Hussain and Kaul (2018) also reported same trend in buckwheat-barley incorporated biscuits. These reports well support our findings regarding increase in fat content with the increase in proportion of barley in multigrain porridge mix. Storage was found to have noteworthy effect on the fat content of multigrain porridge. The mean percent crude fat of the product at the beginning of storage was 2.40 % which decreased significantly to 1.20 % as the storage approaches five months. The decline is likely to be due to the lipolytic activity of enzymes, i.e. lipase and lipoxidase (Haridas et al., 1983 and Leelavathi et al., 1984). The findings of the present investigation are in consonance with that of Murugkar and Jha (2011) and Shahzadi et al. (2005) who also reported decrease in fat content in sprouted soybean flour packed in different packaging materials and in flour blended with various legume flours.

The crude fiber content of multigrain porridge mix is given in Table 4, which illustrates the effect of treatments and storage periods on its crude fibre content and revealed that the mean crude fiber increased from 2.02 to 2.39 % with the supplementation of buckwheat with barley in the porridge which could be due to the higher concentration of crude fibre in barley as compared to the buckwheat. Earlier other workers, (Hussein et al., 2013) reported similar results in balady bread made from wheat flour supplemented with barley flour. So the findings of above authors confirm the present study. With the advancement of storage period (150 days), the mean fibre content decreased significantly from 2.90 to 1.55%. The decrease in crude fibre might be due to the degradation of hemicelluloses and other structural polysaccharides during storage. Heat and moisture solubilizers also degrade pectic substances leading to the decrease in crude fibre content as reported by Sharon and Usha (2006) in bread fruit flour. This observation is agreed with other scientific findings of Singh et al. (2006) in pearl millet cake and Butt et al. (2003) in wheat flour.

The ash content represents the quantity of total minerals. The ash content of multigrain porridge mix (of six samples) is determined from the data in Table 5. The porridge mix prepared from 100 % barley grits (F₂) was found to have highest mean ash content of 2.08 %. The ash content increased with the incorporation of barley grits. In 1987, Bhatty reported that barley usually contains visible specks of bran and subsequently appears darker and is higher in ash content than typical wheat flour. The results also corroborated those of Kawka et al. (1999) who reported an increase in ash content of bread with the substitution of barley flakes in wheat flour. The ash content of 100 % buckwheat porridge mix (F₁) was 1.32 %. The order of the mean ash contents of the blends was found to be as follows; F₃ < F₄ < F₅ < F₆. Upon storage of 150 days, the mean ash content decreased significantly from 1.98 to 1.55 % because the minerals might chelate with other components resulted in less availability. Similar decrease in ash content during 60 days of storage was reported by of Butt et al. (2004) while studying the effect of moisture and packaging and shelf-life of wheat flour. These findings are consistent with the results of previous study on maize based traditional weaning foods (Afoakwa et al., 2006) and wheat flour (Butt et al., 2004).

The treatments significantly (p ≤ 0.05) influenced the carbohydrate content of multigrain porridge mix (Table 6). With increase in the proportion of barley in the product, the mean carbohydrate content decreased significantly (P ≤ 0.05) from 71.60 % (in 0 % BG) to 66.98 % (in 40 % BG) porridge mixes. The decline in carbohydrate content is attributed to its lower concentration in barley as compared to buckwheat. The results are at par with that of Hussein et al. (2013) in balady bread made from wheat flour supplemented with barley flour. The mean carbohydrate content of porridge mix increased significantly from 68.80 % to 70.72 % during 150 days of storage period which might be due to the breakdown of complex polysaccharides into simple sugars. Similar trend was also observed by Sarojini et al. (1996) in rajmah flour and by Varshney et al. (2008) in defated peanut cereal biscuits.

The antioxidant activity (DPPH radical scavenging activity) of the multigrain porridge mix (Table 7) after 30 minutes reaction differed significantly (P ≤ 0.05) with different treatments. Formulation F₆ was exceptionally high in quenching DPPH at 48.02 % and F₁ had the lowest DPPH scavenging capacity (40.69 %) among the blends. Increase in barley proportion in the product led to the increase in DPPH scavenging activity and it is attributed to its possession of maximum quantity of radical inhibitors or scavengers with possibility to act as primary antioxidants. They might react with free radicals, particularly with the peroxy radicals, which are the major propagators of the auto-oxidation chain of fat, thereby terminating the chain reaction (Sharma and Gujral, 2014). In previous studies, Sharma and Gujral (2014) reported increase in the DPPH radical scavenging activity with the increase in barley supplementation in cookies. With the advancement of storage period, the mean scavenging activity of porridge mix declined significantly from 48.87 to 47.16 % and to 38.68 % after 60 and 150 days, respectively. The reason might be due to the degradation of polyphenols which are responsible for the antioxidant activity. Our results are in accordance with the findings of Reddy et al. (2005) and Hussain et al. (2018a) in biscuits.

Economics calculations of prepared multigrain porridge mix are presented in Table 8. The cost of production of porridge mix F₆ (50:40:10::BWG:BG:AP) is based upon the fixed and variable cost of all ingredients used and some other factors viz. processing charges, packaging materials and labels used. The cost of production of porridge mix comes to ₹ 12.88/100g, which is cheaper as compared to commercially available porridge.