In March 2021, the seventy-fifth session of the United Nations General Assembly declared 2023 the International Year of Millets (FAO-2023), following a proposal submitted by the Government of India supported by 72 countries. FAO-2023 mainly focused to increase awareness about benefits of millets, with their nutritional value, health advantages to environmental sustainability and economic potential. Year-2023 facilitated partnership, engaged stakeholders in millet production and promotion and boost public consumption of millets by enhancing collaboration between science and policy. Furthermore, FAO, 2023 encouraged research and development for sustainable, resilient millet production by highlighting new market opportunities for farmers and producers and to produce innovative millet-based products for consumers (FAO, 2023).
       
Pearl millet (Pennisetum glaucum) and sorghum (Sorghum bicolor) are commonly grown crops in the dry and semi-dry region of Africa (Eltayeb et al., 2007). These crops have not been utilised sufficiently and hence, considered underutilised crops even though it is rich in essential nutrients and nutraceutical compounds (Taylor and Duodu, 2015).
       
Pearl millet (Pennisetum glaucum), plays a vital role in ensuring food security in arid regions, it is the sixth most cultivated cereal at global level. It is a significant source of energy and protein, often referred to as the “poor man’s grain,” as it is high in nutritional value (FAO, 2013).
       
Pearl millet, an important coarse-grain cereal and forage crop cultivated in the arid and semi-arid regions of the Indian subcontinent and Africa, plays an important role in providing dietary energy and supporting nutritional security (Bhat et al., 2018). Pearl millet is a good source of important minerals like potassium, calcium, sodium, magnesium and phosphorus. It is especially rich in iron and zinc, which can help to increase haemoglobin levels. Additionally, it contains antioxidants, especially phenolic compounds, which may have anti-cancer benefits (Huang et al., 2020).
       
With the ongoing global issue of food insecurity, there is a growing need to make better use of existing crops to develop nutritious, affordable and attractive food products for people around the world. To meet this goal, various food processing methods are used to increase nutrient availability, enhance taste, texture and reduce anti-nutritional factors in the food (Nanje Gowda  et al., 2022).
       
For the development of off-odours in the flour during storage, the goitrogenic compounds in pearl millet are derivatives of phenolic flavonoids, such as C-glycosyl flavones and their metabolites are responsible (Taylor and Emmambux, 2008).
       
Antinutritional factors, that can bind to metals and inhibit enzymes and reduce the bioavailability of essential nutrients, particularly minerals and proteins. However, now a day, some of these compounds-especially polyphenols-have also been known for their health benefits as it including antioxidant properties (Rao et al., 2017). Different pretreatment and processing methods are applied on food grains, such as de-branning, soaking, germination, fermentation and autoclaving, to reduce antinutrients. These processing methods improve the nutritional quality of food by increasing the bioavailability of minerals like calcium, iron and zinc, as well as enhancing protein absorption (Birania, 2020).
       
Pearl millet consists of a huge amount of inositol hexa-phosphates (IP6), commonly known as phytic acid or phytates. Phytates are considered antinutritional compounds as it reduces the body’s ability to absorb important minerals like calcium, phosphorus, zinc, iron, copper and manganese as it binds with these minerals. Other antinutrients, such as tannins and polyphenols, also limit the grain’s use as a food source. Reducing the level of phytic acid is important because it can improve the nutritional value of pearl millet. As a result, there has been growing interest in finding ways to lower its antinutritional effects (Mahajan and Chauhan, 1987).
       
Hence, this study aimed to evaluate the effect of pretreatments like soaking, roasting and germination on proximate, mineral, antinutritional factors and colour properties of pearl millet, so as to consider possible usage of pearl millet in different value-added product in food system.

Materials
 
The present research work took place during year 2023-2025 at the “College of Food Technology, Vasantrao Naik Marathwada Krishi Vidyapeeth (VNMKV), Parbhani.”
       
Pearl millet grains, purchased from local market of Parbhani, were cleaned to remove dust, sticks, straws and freed from foreign materials including broken. These grains were divided in two batches (1000 g each) used for further processing as each batch was then divided into four (250 g) portions for three pretreatments (soaking, roasting and germination) and one used as a raw sample.

Sample preparation and pretreatments
 
Untreated pearl millet flour
 
Pearl millet grains were cleaned first properly and milled through lab scale hammer mill to get fine flour of 40 mesh size. The untreated pearl millet flour was stored in polyethylene zipper plastic bag at room temperature.
 
Soaked pearl millet flour
 
Pearl millet grains were cleaned first properly, wash it for two to three times with tap water to remove dust, soaked in tap water (1:5) ratio (Khandelwal et al., 2010a) for 12 hrs and dried in a tray drier at 65°C for 4 hrs. After drying cooled it to normal temperature and millet through lab scale hammer mill to get fine flour. The obtained flour was sieved using a 40-mesh sieve. The soaked pearl millet flour was stored in polyethylene zipper plastic bag at room temperature.
 
Roasted pearl millet flour
 
Pearl millet grains were cleaned first properly, roasted it in a pan at 80°C for 10 min. which change the colour of grain and produces the flavour, after roasting cooled it to normal temperature and millet through lab scale hammer mill to get fine flour. The obtained flour was sieved using a 40-mesh sieve. The roasted pearl millet flour was stored in polyethylene zipper plastic bag at room temperature (Kulthe et al., 2022).
 
Germinated pearl millet flour
 
Pearl millet grains were cleaned first properly then wash it for two to three times with tap water to remove dust, soaked it for overnight 12 hrs in 1:5 ratio, after completion of soaking period the excess water was discarded. Soaked grains were tightly bound in a muslin cloth and frequently water was sprayed when needed in a 48 hrs of germination period. The sprouted grains were dried in a tray drier at 65°C for 4 hrs, rootlets were removed and then grains were milled in lab scale hammer mill to get fine flour. The obtained flour was sieved using a 40-mesh sieve. The germinated pearl millet was stored in polyethylene zipper plastic bag at room temperature (Sharma et al., 2015).
 
Proximate composition
 
The proximate analysis of processed pearl millet flour samples was analyzed for moisture, crude fat, crude protein, crude fibre, ash content and carbohydrate content. The analysis was performed by using procedure outlined by (AOAC, 2005).
 
Mineral composition
 
Two gram of defatted processed pearl millet flour was weighed and burned at 550°C. The obtained ash was treated with concentrated hydrochloric acid (HCl) on hot plate for digestion. Then after digestion sample was filtered through Whatman No. 42 filter paper and made volume up to 100 mL using distilled water for mineral analysis by following standard process given by (AOAC, 2005) using atomic absorption spectrophotometer (AAS Model: Varian, AA-240, Victoria, Australia) using air acetylene flame. Calcium, iron, magnesium, zinc was analyzed.
 
Antinutritional factor
 
Tannin and phytic acid analysis were carried out by method given by (Mane et al., 2023). Tannin estimation, about 0.1 mL of sample extract was transferred to a 100 mL volumetric flask containing 75 mL of distilled water. Folin-Denis reagent (5 mL) and sodium carbonate solution (10 mL) were then added and the volume was adjusted to 100 mL with distilled water. The resulting solution was incubated for 30 min. and then the absorbance was recorded against an experimental blank at 760 nm.
       
For the phytate test, the powder sample (0.15 g) was combined with 10 mL of HCl (2.4%) and the extraction was performed using a shaking incubator (1 hr/25–27°C). The resulting solution was centrifuged (3000 rpm/30 min) and filtered to obtain a pure phytate extract. Briefly, 1 mL of Wade reagent (0.3% of sulfosalicyclic and 0.03% FeCl₃.6H₂O acid in water) was mixed with sample extract (3 mL) and vortexed for 5 seconds. The reading was immediately recorded at a wavelength of 500 nm and the results reported as mg/100 g dry basis of sample weight.
 
Colour analysis
 
Colour of processed pearl millet flour evaluated through hunter lab calorimeter (Model No. Color Flex EZ). Hunter lab calorimeter was calibrated with white tile. Average L*, a* and b* values of processed pearl millet flour samples were reported and analysis was carried out in triplicate (Jyotsna et al., 2015).
 
Statistical analysis
 
The data of all experimental treatments were statistically analysed by completely randomized design (CRD) using analysis of variance (ANOVA) (Panse and Shukhatame, 1985).

Proximate composition
 
The effect different pretreatments like soaking, roasting and germination on proximate composition like moisture, crude fat, crude protein, crude fiber, ash and carbohydrate of pearl millet was resulted in Table 1.


       
Moisture content of pearl millet was found to be lower in pretreated pearl millet flour as compared with raw pearl millet flour, in soaked and germinated pearl millet flour moisture content was 9.40% and 8.60% as after giving pretreatments like soaking and germination millet grains were dried which might reduce the moisture content. More reduction occurred during roasting that is from raw 10.46% to 6.74% in roasted pearl millet flour it might be due to evaporating the water during heating. The moisture content of roasted pearl millet flour was reduced, it may be attributed due to the drying effect due to roasting (Komeine et al., 2008).
       
Fat content of pearl millet flour in soaking pretreatment was 4.96%, roasting 5.80% and in germination 4.06%. The fat content of soaked pearl millet flour was found nearabout similar with raw pearl millet flour 5.04%. During roasting fat content was increased it could be due to reduction in moisture content as it will get concentrated, in germinated pearl millet flour it was reduced which might be occur due to during germination process grain use energy and fat content act as energy source which cause reduction in fat content in germinated pearl millet flour (Sade, 2009).
       
Protein content found in soaked, roasted and germinated pearl millet flour was 12.10%, 11.20% and 13.29% respectively. During soaking and germination protein content was increased it might be due to the synthesis of new amino acids (Sharma et al., 2015), while during roasting it was reduced. The decrease in protein content of roasted pearl millet flour might be due to alteration of structures of endogenous protein due to roasting (Fasasi, 2009). Crude fiber content was 2.11% in soaked, 1.90 in roasted and 2.40 in germinated millet flour. Ash content was 2.10% in soaked, 2.25% in roasted and 2.09% in germinated millet flour. Carbohydrate was high in roasted 72.11%, followed by germinated 71.44% and 69.33% in soaked pearl millet flour. Results were similar to (Kulthe et al., 2022). While, in untreated pearl millet flour protein content was 11.40 %, crude fiber was 2.10 %, ash 2.10 % and carbohydrate was about 68.90 %, these findings were closely agreement with (Singh et al., 2017; Mahalakshmi et al., 2024).
 
Mineral composition
 
The mineral composition of processed pearl millet flour was given in Table 2. Effect of soaking, roasting and germination on minerals like calcium, magnesium, iron and zinc was evaluated. 

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The calcium content of germinated pearl millet flour was found to be high 44.23 mg/100 g as compared with untreated pearl millet flour 40.68 mg/100 g. During soaking there was slight increase in calcium content 41.21 mg/100 g whereas low calcium content found in roasted pearl millet flour 38.75 mg/100 g. High temperature during roasting caused the more loss of calcium. Magnesium content was reduced in all pretreatments, during germination it reduced more 112.25 mg/100 g followed by soaking 122.00 mg/100 g and then roasting 124.00 mg/100 g it might be due to utilization during processing.
       
Iron and zinc content during soaking and germination get reduced, Iron during soaking 8.10 and germination 8.25 mg/100 g it might be due to leaching occurs during processing and in roasting it increased 11.20 mg/100 g it might be due to roasting was carried out in iron pan and heat may cause intact without leaching. Zinc showed similar results like iron. The obtained results with respect to minerals in pearl millet flours were more or less similar to earlier reports given in the literature. Decrease in mineral content of roasted pearl millet flour may be attributed to the application of heat which has the tendency to induce both nutritional and biochemical variation in food composition (Yarkwan and Uvir, 2014; Kulthe et al., 2022; Sade, 2009).
 
Antinutritional factor
 
Anti-nutrients like phytic acid and tannins were analyzed for pearl millet flours (Table 3). Processing of pearl millet grains, i.e., soaking, roasting and germination, caused decrease in phytic acid content 550 mg/100 g to 295 mg/100 g, 315 mg/100 g and 200 mg/100 g respectively and Tannin 430 mg/100 g to 157 mg/100 g, 160 mg/100 g and 137 mg/100 g respectively. Variation in phytic acid, tannins and polyphenol content among treated pearl millet flours can be attributed to flour type, extraction rate and both genetic and environmental conditions. Kheterpaul and Chauhan, (1991) reported phytic acid content of pearl millet with a value of 990 mg/100 g, Kumar and Chauhan (1993) reported phytic acid value of 825.7 mg/100 g. Tannins and phytic acid compounds reduces the digestibility of proteins, carbohydrates and minerals as it binds with nutritional component (Linda and Rooney, 2006).

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Colour analysis
 
The colour of the grains and flour was reported in terms of three components viz., colour L*, colour a* and colour b*. L* indicates lightness and the colour intensity for L* varies from 0 (black) to 100 (white) and a* positive value denotes redness; negative value denotes greenness and b* denotes yellowness by positive value and blueness by negative value. The colour of pearl millet grain and pretreated pearl millet flour was analysed and L*, a*, b* values are shown in Table 4.    

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L*, a*, b* value of pearl millet grain was 64.62, 3.23 and 8.68 respectively. L* value was increased in flour form than whole grain colour. L* value of untreated pearl millet flour was 66.73, soaked pearl millet flour 69.96 and germinated pearl millet flour 72.19 while it decreased in roasting 65.60 as during roasting the colour was changed due to Millard reaction (Ibanoglu, 2002); while during soaking and germination L* value was increased, it might be due to leaching of colouring compound in water. In colour of grain, in seed form colour basically represented the colour of seed coat while colour of flour is the mixed effect of colour of all component of grain (Mridula et al., 2008). The a* value of untreated pearl millet flour, soaked pearl millet flour, roasted pearl millet flour and germinated pearl millet flour was 1.19, 1.33, 3.13 and 1.18 respectively. The b* value was 13.79, 12.86, 13.11 and 12.12 of untreated, soaked, roasted and germinated pearl millet flour respectively. Similar results were given by (Gaurav et al., 2021) and (Mercy and Kiruba, 2021).

The results obtained in the study showed that preprocessing treatments had a good impact on the nutritional compositions, minerals and colour attributes of pearl millet. It can also helpful for reduction of antinutritional factors which increases the bioavailability of nutrients.  Soaking, roasting and germination of pearl millet helps to reduce antinutritional factors Among all pretreatment’s germination was found the best as it enhances the nutritional profile of pearl millet.

Authors are thankful to Dr. V. S. Pawar Research guide for constant encouragement and support.
 
Disclaimers
 
The views and opinions expressed in this paper is of author. The author is solely responsible for content and accuracy.
 

The authors declare that there are no conflicts of interest.