Asian Journal of Dairy and Food Research
Chief EditorHarjinder Singh
Print ISSN 0971-4456
Online ISSN 0976-0563
NAAS Rating 5.44
SJR 0.176, CiteScore: 0.357
Chief EditorHarjinder Singh
Print ISSN 0971-4456
Online ISSN 0976-0563
NAAS Rating 5.44
SJR 0.176, CiteScore: 0.357
Processing Driven Impact on Functional and Nutritional Profile of Pearl Millet
Submitted10-08-2022|
Accepted09-12-2022|
First Online 14-12-2022|
Pearl millet (Pennisetum glaucum) is one of the major food crops in most of the arid and semi-arid cropping regions of India being the fourth most important cereal crop. The higher ratio of germ to endosperm is responsible for the higher protein content (Dendy, 1995). Though pearl millet is grown mainly for human consumption, it also serves as fodder for cattle and raw material for cattle feed industries. Though pearl millet is considered as a poor man’s crop, it is rich in protein, fat and mineral contents. It is also rich in zinc and iron comparatively to other cereals.
Pearl millet has a high nutritional value but bioavailability is low, due to presence of anti-nutritional factors, such as phytic acid, polyphenols and tannins. These act on iron and zinc bioavailability (Camara and Amaro, 2003). Depending on their localization in cereal grains, the proportions of these anti-nutrients in diet can be reduced by roasting, malting, germination, etc. (Kheterpaul and Chauhan, 1991). Beside its nutritional availability, pearl millet contains significant amount of inositol hexaphosphates (IP6) generally referred to as phytic acid or phytates. Phytate has been recognized as an antinutritional factor affecting the bioavailability of major minerals such as calcium and phosphorous and trace ones such as zinc, iron, copper and manganese.
Other antinutrients of relevant importance are tannins and polyphenols, which are known to limit the utilization of it as a food. Decreasing of phytic acid is very important and advantageous as well, due to its influence on nutritional aspect. Therefore, interest has been grown to reduce its antinutritional effects (Mahajan and Chauhan, 1987).
Hence, the present investigation was carried out to study the effects of various processing treatments on the chemical composition in reference to enhancement in functional and nutritional profile along with reduction in anti-nutrients in treated pearl millet flours.
Materials
Pearl millet grains, purchased from local market of Pune, were cleaned, freed from foreign materials including broken and shrunken seeds. The seeds were divided into four parts and kept for processing studies.
Processing treatments
Untreated pearl millet flour
Pearl millet grains were properly cleaned and milled in hammer mill (Sanco Valves Pvt. Ltd., Navi Mumbai, India) and sieved through 40 mesh sieve size to obtain plain or untreated pearl millet flour.
Roasted pearl millet flour
Pearl millet grains were properly cleaned and roasted for 10 mins at 80°C, then milled in hammer mill (Sanco Valves Pvt. Ltd., Navi Mumbai, India) and sieved through 40 mesh sieve size to obtain roasted pearl millet flour.
Blanched pearl millet flour
Pearl millet grains were properly cleaned and were blanched at 98°C for 30s followed by sun drying, then milled in hammer mill (Sanco Valves Pvt. Ltd., Navi Mumbai, India) and sieved through 40 mesh sieve size to obtain the blanched pearl millet flour.
Malted pearl millet flour
The pearl millet grains were properly cleaned and were soaked overnight in water at room temperature. Then the grains were placed in muslin cloth and frequently watering was done for full 48 h. The sprouted seeds were then kiln dried at 60°C and rootlets were removed and then grains were milled in hammer mill (Sanco Valves Pvt. Ltd., Navi Mumbai, India) and sieved through 40 mesh sieve size to obtain malted pearl millet flour.
Functional parameters
Water absorption capacity and oil absorption capacity of flours were measured by the centrifugation method described by Sathe et al., (1982) as modified by Fagbemi (2008). Emulsion activity and Emulsion stability were calculated as described by Yasumatsu et al. (1972). Foam capacity and Foam stability were estimated as described by Narayana and Narsinga Rao (1982). Swelling power and water solubility were determined by centrifuge method described by Sosulski (1962) with slight modification.
Proximate composition
Processed PMF samples were evaluated for moisture, crude fat, crude protein, crude fibre, ash content and carbohydrate using standard methods (AOAC, 2005).
Mineral composition
Mineral analysis of processed PMFs was carried out on samples digested with hydrochloric acid. Minerals calcium was estimated titrimetrically by standard method (AOAC, 2005). Total iron was analyzed by colorimetric method given by Ranganna (1986). Total phosphorous content was estimated by colorimetric method as described by Chapman and Pratt (1982).
Antinutritional factors
Processed PMFs were assessed for various anti-nutritional factors viz. phytic acid, tannins and total polyphenols. Phytic acid was determined by standard procedure of Wheeler and Ferrel (1971). The tannin content was determined by calorimetric method using Folin-Denis reagent whereas total polyphenols content was determined by modified Folin-Ciocalteu calorimetric method using gallic acid as standard (AOAC, 2005).
Statistical analysis
Each sample was analyzed in triplicate. The figures then were averaged. The data obtained was analyzed statistically using standard methods given by Snedecor and Cochran (1990) and by Duncan’s multiple range test with the probability p≤0.05 (Duncan, 1955).
Functional properties
Water holding capacity means the ability of flours to hold water which plays an important role as a functional attribute of the flours. From data recorded for the functional properties of processed PMFs (Table 1), it was observed that processing of pearl millet grains i.e., roasting, blanching and malting significantly affected the water holding capacity of respective flours. Samples treated with roasting and blanching processes showed increase while those treated with malting process showed decrease in water holding capacity as compared to untreated PMF. This variation in water holding capacity of processed PMF may be due to changes in particle size and the protein content of the flour due to processing (Kinsella, 1976).
The results obtained in the present investigation and with reference to observations of various researchers, it is reported that processing of pearl millet grains can be helpful in obtaining desired effect in functional properties and nutritional profile. Also, processing of pearl millet by roasting, blanching and malting can be useful in destruction of antinutrients with increased bioavailability of essential nutrients. Among all treatments, malting recorded better results in terms of improvement in both functional and nutritional profile of pearl millet.
The authors declare that there are no conflicts of interest regarding the publication of this article. No funding or sponsorship influenced the design of the study, data collection, analysis, decision to publish, or preparation of the manuscript.
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