Development, optimization and nutritional characterization of millet spread to combat hidden hunger

Introduction

Hidden hunger refers to a form of micronutrient malnutrition that occurs when an individual's diet provides sufficient calories but lacks adequate vitamins and minerals necessary for proper growth, development, and physiological functioning. Unlike overt hunger, which is visible through undernutrition or emaciation, hidden hunger often goes unnoticed because affected individuals may appear to be consuming enough food and may not show immediate physical symptoms (Muthayya et al., 2013) [11] . The primary cause of hidden hunger is poor dietary quality. Diets that rely heavily on staple cereals (such as rice, wheat, or maize) often lack diversity and fail to provide essential micronutrients like iron, zinc, iodine, vitamin A, and folate. Other contributing factors include: Poverty and limited access to nutrient-rich foods (e.g., fruits, vegetables, legumes, animal products) (FAO, 2013) [7] . Soil nutrient depletion, which affects the micronutrient content of crops (White & Broadley, 2009) [19] . Poor health and sanitation, which can impair nutrient absorption (Black et al., 2008) [4] . Hidden hunger can have profound health, developmental, and economic impacts, especially on women and children. Deficiencies in micronutrients lead to: Impaired cognitive development and learning capacity in children (Grantham-McGregor et al., 2007) [9] . Weakened immune systems, increasing susceptibility to infections (Bhutta et al., 2013) [3] . Increased maternal and child mortality, particularly due to deficiencies in iron, vitamin A, and iodine (Black et al., 2013) [11] . Reduced productivity and economic growth, as malnourished individuals are less able to work effectively, perpetuating cycles of poverty and malnutrition (Stein & Qaim, 2007) [15] . Globally, over 2 billion people suffer from hidden hunger, with the highest burden in low-and middle-income countries, particularly in South Asia and Sub-Saharan Africa (WHO, 2020) [20] . Women of reproductive age and children under five are the most vulnerable groups. Millets, being naturally rich in iron, calcium, fiber, and antioxidants, are increasingly being explored as sustainable options to combat hidden hunger through the development of value-added products such as spreads, snacks, and flours.

Finger millet (Eleusine coracana L. Gaertn.), also known as ragi in India, is a small-seeded cereal crop widely cultivated in Africa and South Asia. Finger millet is valued for its high nutritional content, climate resilience, and long shelf life, making it a promising crop to address food and nutritional security, especially in developing countries (Upadhyaya et al., 2007) [18] . Finger millet is rich in carbohydrates, dietary fiber, calcium, iron, and essential amino acids, making it superior to many major cereals such as rice and wheat in several aspects (Antony et al., 1997) [1] . Calcium levels in finger millet are 10 times higher than rice and 3-5 times higher than wheat, making it an excellent food for children, pregnant women, and the elderly (Rao et al., 2017) [12] . Finger millet contains several bioactive compounds such as phenolic acids (e.g., ferulic acid, caffeic acid), flavonoids, tannins (in pigmented varieties), phytates and dietary fiberassociated compounds. These compounds exhibit antioxidant, anti-inflammatory, and antimicrobial activities, which may contribute to lower risks of chronic diseases (Devi et al., 2014) [6] . Whereas, barnyard millet is a minor cereal often referred to as a "climate-resilient crop" because of its ability to grow under diverse and adverse agro-climatic conditions. Barnyard millet is gaining popularity as a nutri-cereal due to its high nutrient density, fast growth cycle, and suitability for sustainable farming systems (Saleh et al., 2013) [13] . Barnyard millet offers several health-promoting benefits due to its unique nutrient and phytochemical profile (Ugare et al., 2014) [17] . Barnyard millet is particularly valued for its high fiber content, low glycemic index, and a favorable macronutrient-to-micronutrient balance compared to polished rice and wheat (Gopalan et al., 2011) [8] . Iron content in barnyard millet is often 2-5 times higher than that of rice, making it a valuable cereal in combating irondeficiency anemia. Its polyphenols contribute to antioxidant activity, potentially reducing risk of chronic diseases such as diabetes and cardiovascular disorders (Shobana et al., 2013) [14] . Sweet potato is a rich source of energy, carbohydrates, vitamins (especially vitamin A in orange-fleshed varieties), minerals, dietary fiber, and antioxidants. Its composition varies with variety, flesh color, and growing conditions (Bovell-Benjamin, 2007) [5] . Sweet potato is notable for its provitamin A carotenoids, particularly in orange-fleshed varieties (OFSP), which can significantly contribute to vitamin A requirements, especially in children and women in developing countries (Hagenimana et al., 1998) [10] . Sweet potato contains various bioactive compounds with healthpromoting properties: Carotenoids (β-carotene, lutein, zeaxanthin): Especially abundant in orange-and yellowfleshed varieties. Anthocyanins: Predominant in purplefleshed varieties; act as potent antioxidants. Phenolic acids: Chlorogenic acid, caffeic acid, and others contribute to antioxidant capacity (Troung et al., 2007) [16] Materials and Methods Selection of raw materials Barnyard millet, finger millet and sweet potato were collected from local market of Kanpur, Uttar Pradesh, India. Other supporting ingredients like anjeer, sesame seeds, fresh milk etc. also collected from local market of Kanpur.

Processing of Finger and Barnyard millet

Firstly, millets were thoroughly cleaned to remove unwanted foreign materials. For the preparation of spread both the millets (finger and barnyard) were soaked whole night just double amount of water (w/v). Next day, water was drained and washed under tap water 2-3 times to remove dirt. After that, grind it by adding fresh and clear water; extract was collected through muslin cloth.

Processing of Sweet potato

Fresh purple skin sweet potato was purchased; wash it carefully to remove soil and dirt. After that peeled it with the help of peeler and sliced it very thin through slicer. Boil the water, add sweet potato slices and remain in water for 2-3 minutes, dried it under sun rays. The fully dried sweet potato slices were collected and grinded to make fine powder; put in air tight container till further use.

Preparation of other ingredients

Sesame seeds and anjeer were collected from local market, clean it properly to remove stones, duplicate materials etc. and put it in air tight container till further use.

Formulation of different proportions of millet spread

Total five treatments including control of millet spread were prepared at varying proportions of millets and sweet potato. The Table 1 illustrated below depicts different ratios of treatments for the preparation of millet spread.

Minerals

Minerals viz. iron and zinc were estimated by AAS (Atomic Absorption Spectrophotometer). The desired samples in liquid form were sprayed into the flame of an AAS, whereas absorption or emission of the minerals to be analyzed was measured at a specific wavelength.

Sensory evaluation

The sensory evaluation and organoleptic quality of millet spread was evaluated by nine point hedonic rating scale.

Statistical Analysis

All samples were taken in triplicates and presented as a mean ± SD. OPSTAT software was used to analyze the data of nutritional composition and sensory evaluation of millet spread. The one way ANOVA was used to measure the significant differences. The findings of sensory evaluation are given in Table 2 and Fig 2 . Treatment T 2 scored highest in appearance i.e. 8.83 followed by T 3 , T 1 , T 4 and least by control (T 0 ) i.e. 6.01. Therefore, significant difference was found among each other when compared with control at 5% level of probability. Furthermore, regarding color treatment T 2 (8.92) scored well including T 3 , T 1 , T 4 and minimally by control (6.52) which is not good in color. Statistically, when compared with control all treatments of millet spread found significant each other having at 5% level of probability. Taste is one of the five basic human senses and refers specifically to the perception of flavor sensations detected by the taste buds on the tongue and other areas of the oral cavity. However, millet spread developed from treatment T2 (8.88) first position in score in addition to T 3 , T 1 , T 4 and least by control (T 0 ) i.e. 6.22. Statistical analysis revealed that all millet spread treatments were significantly different from the control, with a nominal p-value of 0.00 at the 5% level of significance. On the other hand, treatment T 2 (8.66) was perfect in texture and rated highest than others; while, treatment T 3 was the next followed by T 4 , T 1 and lastly T 0 (6.93). All treatments of millet spread showed statistically significant differences compared to the control, with a pvalue of 0.01, indicating significance at the 5% probability level. While in case of flavor, millet spread prepared from treatment T 2 (8.72) found highest score along with T 3 , T 1 , T 4 and least by control (T 0 ) i.e.6.10. However, statistical data depicts that all treatments were significantly differ with each other in contrast to control (P<0.05). Lastly, about overall acceptability of treatments prepared from millet spread elevated score seems to be in T 2 (8.80) thereafter T 3 , T 1 , T 4 and lowest in T 0 (6.35) among all. Analysis showed that all treatments were significantly different from one another, with a p-value of 0.00 at the 5% significance level Nutritional composition of millet spread

Results and Discussion

Proximate composition of millet spread

The proximate composition and physiological energy values of various treatments of millet spread are represented in Table 3.

Physiological Energy:

In case of physiological energy content, highest mean score value seen in treatment T4 (195.05±2.84) succeeded by T 2 , T 3 , T 1 and minimum energy content in control (T 0 ) i.e. 162.55±5.98. Therefore, statistically energy revealed a highly significant treatment effect when compared with control having p value = 0.01 at 5% level of probability.

Moisture content: However, moisture content (g/100g) showed an inverse trend, decreasing from 58.85% in T 0 to 47.01% in T 2 , with a mean of 51.04%. While, from the Table 3 highest moisture content seen in control (58.85±0.54) followed by T 1 , T 4 , T 3 and lowest in T 2 (47.01±0.34). The ANOVA for moisture showed a highly significant treatment effect among each other at 5% level of probability.

Ash content:

The ash content (g/100g) from Table 3 found highest in T 2 (1.90±0.25) subsequently, T 3 , T 1 , T 4 and lowest in T 0 (0.60±0.02). Ash increased markedly from 0.60% (T 0 ) to 1.90% (T 3 ), showing that treatments enhanced mineral composition compared to control. Statistically when compared all treatments with control then a highly significant effect was found in each other at 5% level of probability and demonstrating that mineral content was positively influenced by treatment application.

Crude Protein content: With regard to protein content (g/100g), its levels improved markedly with treatments, rising from 2.94% (T0) to a maximum of 6.77% (T 2 ), yielding a mean of 5.06%. From Table 3 it was depicted that maximum protein found in treatment T 2 (6.77±0.23) including T 3 , T 1 , T 4 and minimum in T0 (2.94±0.06) respectively. Statistically, data was showed a highly significant difference (p-value = 0.00) observed between one and other treatments at 5% level of probability (P<0.05).

Crude Fat content:

In case of fat content (g/100g) which increased from 2.79% in T0 to 4.57% in T 4 , with a mean of 3.98%. The given Table 3 represents the highest amount of fat seen in treatment T 4 (4.57±0.43) in addition to T 1 , T 2 , T 2 and lowest in T 0 (2.79±0.17). Statistical result indicated that the significant difference manifested between (P<0.05) all treatment compared to control.

Dietary Fibre content: Concerning to dietary fibre (g/100g) content which is presented in Table 3. Fibre increased from 3.40% (T 0 ) to 6.51% (T 2 ), showing that enrichment substantially improved functional quality. The highest dietary fibre seen in treatment T 2 (6.51±0.62) followed by T 3 , T 1 , T 4 and minimal amount in T 0 (3.40±0.53). Statistically, results indicated a strong treatment effect among each treatment.

Carbohydrate content

The carbohydrate content (g/100g), from Table 3 found maximum in treatment T 4 (33.83±0.33) after that T 2 , T 1 , T 3 and minimum in T 0 (31.42±1.00). Carbohydrate content remained relatively stable (32.66 35.72%). Statistically, treatment effect was showed significant difference at 5% level of probability.

Minerals

The iron and zinc of millet spread presented in Table 4. Statistically, significant difference (p-value = 0.01) found among each other when compared to control (P<0.0).

Zinc content:

In connection with zinc (Zn) content (mg/100g); zinc content improved significantly, ranging from 0.07 mg (T o ) to 2.01 mg (T 2 ). However, increased amount seen in treatment T 2 (2.01) subsequently, treatment T 3 , T 1 , T 4 and lastly in control (T 0 ) i.e. 0.07. ANOVA findings represents p value negligible (0.00); means significant difference found (P<0.0) each other in contrast with control.

Conclusion

From the above findings it was concluded that micronutrients rich spread was developed prepared from base ingredients viz. finger millet, barnyard millet and sweet potato as well as other supporting ingredients. Among five combinations at different level of proportions, treatment T2 (38g barnyard, 50g finger millet and 5g sweet potato) found to be best in sensory evaluation and overall acceptability. The millet spread is nutritionally rich in terms of protein, dietary fibre, iron, zinc and low in crude fat which enhances nutritional health status of individuals. All treatments of millet spread good in nutritional value, promote healthier choice as well as mitigate micronutrient deficiencies and day-to-day lifestyle disorders.

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