Pearl millet protein bar: nutritional, organoleptic, textural characterization, and in-vitro protein and starch digestibility

The effect of co-precipitation and high-pressure treatment on functional and structural properties of millet and moringa protein

Protein co-precipitation overcomes the limitations of individual proteins and improves their nutritional profile and functional properties. This study examined the impact of co-precipitation and high-pressure (HP) treatment on millet-moringa protein co-precipitate structure and functional properties. The co-precipitation has significantly (p < 0.05) improved the water holding (4.17 ± 0.02 g/g), oil holding (7.49 ± 0.16 g/g) capacity, and emulsifying stability index (60.72 ± 2.00 %). The increase in zeta potential and decrease in particle size were observed in co-precipitated samples, which explains their high solubility. Circular dichroism (CD) spectra results depict a change in the secondary structure of protein during the co-precipitation and HP treatment. The co-precipitation and HP treatment have significantly increased the invitro protein digestibility of millet and moringa leaf protein isolates. According to the findings, co-precipitation and HP treatment could be an effective method for enhancing the functional properties of millet and moringa protein.

Effects of ultrasound and high-pressure assisted extraction of pearl millet protein isolate: Functional, digestibility, and structural properties

This study explores the effect of individual and combination treatments of ultrasound (US) and high pressure (HP) on the extraction of pearl millet protein isolate (PMPI). Compared to the conventional extraction technique (control) the millets treated with non-thermal techniques provided a higher protein recovery percentage. The highest recovery of 63.43 % was observed in the high-pressure and ultrasound combination (HU) treatment. The solubility of PMPI was significantly enhanced in all pH levels, the highest solubility was observed at pH 10. Combination treatments demonstrated superior functional properties, including emulsifying capacity, foaming property, surface hydrophobicity, water-holding capacity (WHC), and oil-holding capacity (OHC) compared to individual treatments and control. Significant improvement in protein in-vitro digestibility (IVPD) was identified in non-thermal treated PMPI. The involvement of nonthermal techniques for protein extraction significantly altered the protein's secondary structure, surface characteristics, and molecular weight. These findings underscore the application and advantage of combination treatments in the extraction of millet protein isolates.

Optimizing Protein Bars With Whey Protein Isolate, Pea Protein Isolate, and Blue Whiting (Micromesistius poutassou) Fish Protein Hydrolysate: A Simplex-Centroid Mixture Design Study

The aim of this study was to use blue whiting fish protein hydrolysate (BWFPH) as a novel dietary amino acid supplement in whey protein isolate (WPI) and pea protein isolate (PPI)-based protein bars. The findings indicate that incorporating BWFPH significantly influenced the nutritional profile of the protein bars, leading to a ~93% reduction in hardness compared to bars without the hydrolysate. Additionally, BWFPH effectively delayed the hardening process during storage. However, sensory evaluation revealed that the inclusion of BWFPH adversely affected the sensory characteristics, indicating a need for optimization. Using a simplex centroid mixture design, we identified an optimized protein blend compromising 76.02% WPI, 6.72% PPI, and 17.26% BWPFH, which achieved a balance of improved texture and sensory appeal. These results suggest that high-protein bars can be enhanced by integrating novel protein sources through careful formulation and optimization.

Nutritional, Textural, and Sensory Attributes of Protein Bars Formulated with Mycoproteins

Research accumulated over the past decades has shown that mycoprotein could serve as a healthy and safe alternative protein source, offering a viable substitute for animal- and plant-derived proteins. This study evaluated the impact of substituting whey protein with fungal-derived mycoprotein at different levels (10%, 20%, and 30%) on the quality of high-protein nutrition bars (HPNBs). It focused on nutritional content, textural changes over storage, and sensory properties. Initially, all bars displayed similar hardness, but storage time significantly affected textural properties. In the early storage period (0-5 days), hardness increased at a modest rate of 0.206 N/day to 0.403 N/day. This rate dramatically escalated from 1.13 N/day to 1.36 N/day after 5 days, indicating a substantial textural deterioration over time. Bars with lower mycoprotein levels (10%) exhibited slower hardening rates compared with those with higher substitution levels (20% and 30%), pointing to a correlation between mycoprotein content and increased bar hardness during storage. Protein digestibility was assessed through in vitro gastric and intestinal phases. Bars with no or low-to-medium levels of mycoprotein substitution (PB00, PB10, and PB20) showed significantly higher digestibility (40.3~43.8%) compared with those with the highest mycoprotein content (PB30, 32.9%). However, digestibility rates for all mycoprotein-enriched bars were lower than those observed for whey-protein-only bars (PB00, 84.5%), especially by the end of the intestinal digestion phase. The introduction of mycoprotein enriched the bars' dietary fiber content and improved their odor, attributing a fresh mushroom-like smell. These findings suggest that modest levels of mycoprotein can enhance nutritional value and maintain sensory quality, although higher substitution levels adversely affect texture and protein digestibility. This study underscores the potential of mycoprotein as a functional ingredient in HPNBs, balancing nutritional enhancement with sensory acceptability, while also highlighting the challenges of textural deterioration and reduced protein digestibility at higher substitution levels.

A comparative study on comprehensive nutritional profiling of indigenous non-bio-fortified and bio-fortified varieties and bio-fortified hybrids of pearl millets

Seven indigenous pearl millet varieties, including non-bio-fortified (HC-10 & HC-20) and bio-fortified (Dhanashakti) and bio-fortified hybrids, viz., AHB-1200, HHB-299, HHB-311, and RHB-233, were studied in the present work. There was not any significant difference observed in the crucial anti-nutrients content, i.e., phytate (24.88-32.56 mg/g), tannin (3.07-4.35 mg/g), and oxalate (0.33-0.43 mg/g). Phytochemical content and antioxidant activity showed significantly high (p < 0.05) TPC and FRAP, TFC, and DPPH radical scavenging activity in the HHB 299 and Dhanashakti, respectively. Quantitative analysis of polyphenols by HPLC (first report on these varieties) revealed that HHB-299 has the highest amount of gallic acid. Fatty acid profiling by GC-FID showed that Dhanashakti, AHB-1200, and HHB-299 have rich monounsaturated fatty acid (MUFA) and polyunsaturated fatty acids (PUFA). Mineral analysis by ICP-OES showed high iron (87.79 and 84.26 mg/kg) and zinc (55.05 and 52.43 mg/kg) content in the HHB-311 and Dhanashakti, respectively. Results of the present study would help facilitate the formulation of various processed functional food products (RTC/RTE) that are currently not reported/unavailable.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05452-x.

Trends in millet and pseudomillet proteins - Characterization, processing and food applications

Millets are small-seeded crops which have been well adopted globally owing to their high concentration of macro and micronutrients such as protein, dietary fibre, essential fatty acids, minerals and vitamins. Considering their climate resilience and potential role in nutritional and health security, the year 2023 has been declared as 'International Year of Millets' by the United Nations. Cereals being the major nutrient vehicle for a majority population, and proteins being the second most abundant nutrient in millets, these grains can be a suitable alternative for plant-based proteins. Therefore, this review was written with an aim to succinctly provide an overview of the available literature take on the characterization, processing and applications of millet-based proteins. This information would play an important role in realizing the research gap restricting the utilization of complete potential of millet proteins. This can be further used by researchers and food industries for understanding the scope of millet proteins as an ingredient for novel food product development.

Cereal bar functionalised with non-conventional alfalfa and dhaincha protein isolates: quality characteristics, nutritional composition and antioxidant activity

The utilization of conventional protein sources like gluten, soy, dairy proteins, and nuts in the development of protein-enriched cereal bars presents a challenge for their consumption by the population suffering from celiac and other food protein allergies. In the present investigation, protein-rich cereal bars were developed using non-conventional protein isolates (alfalfa and dhiancha (API & DPI) and were evaluated for their quality attributes, nutritional composition, and bioactive potential. The incorporation of protein isolates increased the weight, density, and non-enzymatic browning and decreased the water activity in the bars. The hardness of the bar increased with the addition of protein isolates; however, reduced hardness was observed at 7.5 and 10% levels of API. Supplementation with protein isolates enhanced the protein content (7.83-16.71%), total phenols (1642-4956 GAE μg/g), total flavonoids (268-984 QE μg/g), DPPH radical scavenging activity (96.38-114.82 TEAC μmol/100 g) and reducing power (1926-3586 AAE μg/g) of the bars. Cereal bars maintained good sensory score and overall acceptability at 10 and 5% level of incorporation of API and DPI respectively.

Understanding the Antinutritional Factors and Bioactive Compounds of Kodo Millet (Paspalum scrobiculatum) and Little Millet (Panicum sumatrense)

Kodo and little millet (Kutki) have a variety of phytochemical constituents including derivatives of hydroxybenzoic acid and hydroxycinnamic acids, myricetin, catechin, luteolin, apigenin, daidzein, naringenin, kaempferol, and quercetin with vast health benefits and thus can be utilized as functional food ingredients. Millet-based foods and their food products have physiological and health-promoting impacts, notably antidiabetic, anti-obesity, and cardiovascular disease, and based on the actions of phytochemicals, it plays a major role in the body’s immune system. However, antinutrients (tannins, oxalate, trypsin inhibitor, and phytates) present in these millets restrict their utilization since these factors bind the essential nutrients and make them unavailable. Therefore, this review suggested overcoming the effects of antinutrients in these millets, thereby opening up important applications in food industries that may promote the development of novel functional foods. Various methods were discussed to eliminate the antinutrient factors in these millets, and hence, the review holds immense significance to the food industry for effectively utilizing these millets to develop value-added RTE/RTC products/functional food/beverages.

Millet: A review of its nutritional and functional changes during processing

Millets are a major source of human food, and their production has been steadily increasing in the last decades to meet the dietary requirements of the increasing world population. Millets are an excellent source of all essential nutrients like protein, carbohydrates, fat, minerals, vitamins, and bioactive compounds. However, the nutrients, bioactive compounds, and functions of cereal grains can be influenced by the food preparation techniques such as decortication/dehulling, soaking, germination/malting, milling, fermentation, etc. This study discusses the nutritional and functional changes in millet during different traditional/modern processing techniques, based on more than 100 articles between 2013 and 2020 from Web of Science, Google Scholar, FAO, and USDA databases. Our results concluded that processing techniques could be useful to combat undernourishment and other health issues. Moreover, this review provides detailed information about millet processing, which is advantageous for industry, consumers, and researchers in this area.

Lentinula edodes mushroom as an ingredient to enhance the nutritional and functional properties of cereal bars

Lentinula edodes (shiitake) is the second most cultivated edible mushroom in the world; it has low lipid contents, high protein and it is source of vitamins and minerals. This study aimed to develop and to evaluate two sweet and two salty food bars containing shiitake. The binder elements were heated and then the dried elements were added. The bars were shaped, and the sensorial test was accomplished with hedonic scale of 9 points for analysis of texture, aroma, taste and appearance, and a 5-point scale for buying intention. The centesimal composition included percentages of moisture content, ashes, lipids, proteins and carbohydrate contents. Chemical elements of shiitake were quantified by Energy Dispersive X-ray Fluorescence. Glucans were determined using a commercial kit. Phenolic compounds were determined with the Folin-Ciocalteu reagent. The shelf life was evaluated by microbiological control, up to 180 days, at temperatures of 25 °C and 37 °C. The sweet bar 1 (SwB1) had better sensory analysis and buying intention. Shiitake showed high concentrations of calcium, iron, phosphorus, potassium, zinc, manganese, phenolic compounds and glucans. SwB1-bar maintained shiitake nutritional characteristics. SwB1-bars did not present microorganisms for up to 180 days of shelf life, neither at 25 °C nor at 37 °C, and they followed the standards determined by National Health Surveillance Agency. Sweet bars are an easy marketing alternative due to their stability, low-cost of production and good acceptance, as well as flexibility to add other functional ingredients beneficial to health, such as shiitake.