Development of Barnyard Millet-Honey Blended Dietetic Lassi

Lassi, widely consumed as a fermented milk beverage, is characterized by a creamy consistency, smooth texture, glossy shine and a white colour with a yellowish tinge in good quality. It should also taste mild to highly acidic and have a rich, sweet aroma. According to national tastes, the beverage is usually flavoured with either sugar or salt along with additional spices (Ben et al., 2020). Being an ubiquitous lactic acid fermented milk beverage of the Indian sub-continent, lassi contains a significant amount of milk proteins and phospholipids, along with various metabolites produced by lactic acid bacteria (Sharma et al., 2016). Though lassi is a favourite beverage for all age groups due to its refreshing, tasty and nutritious characteristics as well as its high therapeutic value along with ability to quench thirst, its short shelf life and whey syneresis make it challenging to sell on the market (Krishna et al., 2019). Microorganism metabolism may occur while refrigerated storage, which leads to post-acidification and proteolysis which reduce product quality and reduce lassi shelf life. The quality and acceptability of lassi are determined by these processes based on the degree of acidity (Ashwani et al., 2003).
       
Barnyard millet (Echinochloa frumentacea) belongs to the family Poaceae and is one of the oldest domesticated small millets. This millet is cultivated extensively in several countries, including India, China, Japan, Malaysia, the East Indies, Africa and the United States of America. Its nutritional richness and capacity to adapt to a variety of environmental situations make it a popular staple meal in many areas (Kaur and Sharma, 2020). Barnyard millet serves as a valuable source of protein, carbohydrates and fibre. Compared to other main grains, it notably has higher quantities of important micronutrients including zinc and iron. The nutritional composition of Barnyard millet includes protein (6-13 g), carbohydrates (55-65.5 g), fat (2-4 g), crude fiber (9.5-14 g), mineral matter (3.8-4.5 g), calcium (11-27.1 mg), phosphorus (280-340 mg) and iron (15-19.5 mg) (Ugare et al., 2014). Furthermore, owing to low glycaemic index and gluten, barnyard millet provides extra health benefits including prevention and treatment against several kinds of illnesses, viz. blood pressure regulation, diabetes, obesity, celiac disorder and cardiovascular disease. Moreover, the major fatty acid profile of barnyard millet is linoleic acid, with palmitic and oleic acids (Singh  et al., 2022).
       
The Codex alimentarius commission (CAC) defines “honey” as a naturally sweet material produced by honeybees. The sweetness of honey is due to the presence of carbohydrates in the form of maltose, isomaltose, maltulose, sucrose, turanose, fructose, glucose and monosaccharides and disaccharides. It is like sucrose in terms of sweetness. Additionally, it has enzymes including amylase, oxidase peroxide, catalase and acid phosphorylase as well as oligosaccharides like anderose and panose. In addition to these nutrients, honey has antioxidants, minerals, iron, zinc, trace vitamin B, vitamin B6, vitamin C, niacin and folic acid (Meo et al., 2017). According to research by Kadam et al., (2018), honey may be useful in raising the populations of probiotic bacteria in the gut, which might help to improve digestion, lower cholesterol and prevent colon cancer in addition to boosting the immune system.
       
Hence, the present investigation was undertaken for the process standardization and quality assessment of Barnyard millet-honey blended dietetic lassi and effect of packaging materials on the storage stability of the prepared lassi.

Raw materials and probiotic starter strains
 
Milk, Barnyard millet, sugar and honey were procured from local market of Pune. The Lactobacillus fermentum (NCIM-2165) strain was procured from National Chemical Laboratory (NCL), Pune. The culture was stored at 5±2^oC. Prior to use, culture was activated in suitable medium by incubating at 37^oC for 24 h.
 
Standardization of Barnyard millet-honey dietetic lassi
 
Preliminary trials were conducted to standardize the level of Barnyard millet(0, 5, 7.5, 10%) and honey (0, 5, 7.5, 10, 12.5%)in lassi. The standardization process was undertaken step wise first for Barnyard millet followed by honey in the lassi sample with acceptable level of Barnyard millet subjecting to sensory evaluation by 10 semi trained panel of judges.
 
Preparation of dietetic Lassi
 
The Barnyard millet-honey blended dietetic lassi was prepared as per method Pardhi et al., (2014) with some modification Fig 1.


 
Sensory evaluation
 
The prepared lassi samples were evaluated for sensory attributes by a panel of 10 semi-trained judges, as described by Amerine et al., (1965) using a 9-point Hedonic scale system for different parameters like colour and appearance, flavour, taste, texture, mouthfeel, consistency and overall acceptability. The mean values of 10 semi-trained judges were considered for evaluating the quality.
 
Physico-chemical parameters for raw material and lassi
 
Physico-chemical analysis of raw materials and dietetic lassi included several tests like total soluble solids (TSS), ash, fibre, total phenolic content (AOAC, 1990), pH (Jan et al., 2016), titratable acidity, consistency (Ranganna, 1997), total solids, fat content, protein content (IS: SP-18 1981), ascorbic acid and antioxidant activity (Shimada et al., 1992).
 
Energy value
 
The energy value of dietetic lassi was estimated using the sum of the product of respective physiological fuel values and contents of protein, carbohydrate and fat. It was expressed in Kcal (Kulthe et al., 2018b).

Microbial analysis of lassi
 
Microbial analysis of dietetic lassi included total viable count, yeast and mold counts and coliform count determined by standard method (Tharmaraj and Shah, 2003, Marshall, 1993 and Houghtby et al., 1992).
 
Storage study
 
Dietetic lassi samples were packed in different packages viz. glass bottles, PET bottles and LDPE pouches and stored at refrigeration temperature (5±2^oC) to assess the shelf life and to study the storage related changes in the products. The samples were analyzed periodically for sensory, chemical and microbiological parameters.
 
Statistical analysis
 
Each sample was analysed in triplicate. The figures then were averaged. The data obtained was analysed statistically using standard methods given by Snedecor and Cochran (1990) and by Duncan’s multiple range test with the probability p≤0.05 (Duncan, 1995).

The research aimed to the process standardization and quality assessment of a dietetic lassi formulated with Barnyard millet and honey. The research progressed to standardizing the Barnyard Millet-honey blended dietetic lassi using the selected LAB strain, followed by rigorous sensory, physicochemical and microbial quality assessments. A techno-economic feasibility analysis, supported by product stability studies, demonstrated promising commercialization potential.
 
Physico-chemical analysis of raw materials
 
This study investigates the physico-chemical properties of milk, barnyard millet and honey, key ingredients in a nutritious lassi formulation Table 1. Milk, with its high moisture content (86.60%) and significant caloric value (68.82 kcal), provides essential hydration and energy, containing 3.49% fat, 2.42% protein, 0.65% ash and 6.93% carbohydrates, aligning with previous research by Ghule (2015) and Jadhav (2002). Barnyard millet, noted for its low moisture (12.21%) and high fiber content (8.25%), supports digestive health and offers a robust nutritional profile with 3.25% ash, 6.85% protein, 4.21% fat and 73.50% carbohydrates, contributing 359.29 kcal, consistent with Ugare et al., (2014).


       
Honey stands out with its low fat (0.26%) and protein (0.62%) levels but high carbohydrate content (82.83%) and substantial caloric value (336.17 kcal), enhanced by significant reducing sugars (54.65 mg/100 g) and ascorbic acid (19.65 mg/100 g), boosting its antioxidant properties. The total phenolic content and antioxidant activities of milk (4.97 and 3.45 mg/100 g, respectively), barnyard millet (22.63 and 48.31 mg/100 g) and honey (120.89 and 30.91 mg/100 g) underscore the combined nutritional and health benefits of these ingredients, particularly showing honey’s role in enhancing the lassi’s nutritional value.
 
Standardization of Barnyard millet-honey blend of dietetic lassi
 
In the context of this study, sensory evaluation was conducted to evaluate the sensory characteristics of dietetic lassi formulations containing different concentrations of barnyard millet and honey Fig 2. The study standardized the curd-to-barnyard millet ratio in dietetic lassi, using samples with 0, 5, 7.5 and 10% barnyard millet, respectively. On the basis of sensory evaluation (Fig 2a), treatment B₂ (7.5% barnyard millet) secured the highest scores for colour (8.19), texture (8.19), flavour (7.97), mouthfeel (8.08) and overall acceptability (7.97). Thus, B2 was selected for further research due to its superior sensory profile. These findings align with previous studies by Pardhi et al., (2014) and Das (2015).


       
The standardized barnyard millet lassi (B2-7.5%) was added with different levels of honey (0, 5, 7.5, 10 and 12.5%) for further standardization using sensory evaluation (Fig 2b). Sensory evaluation revealed that B₂H₂ (7.5% honey) had the highest scores for colour (8.33), texture (8.22) and overall acceptability (7.9), indicating optimal sensory performance. Comparatively, other samples showed good but slightly lower overall sensory performance compared to B₂H₂. The results were found consistent with literature (Riazi et al., 2012 and Ghadge et al., 2008).
       
The comparative sensory analysis of selected lassi formulations B₀, B₂ and B₂H₂ revealed distinct profiles (Fig 2 c). B0 scored 8.2 for colour, 7.7 for flavour, 7.85 for texture, 7.65 for taste, 7.95 for mouthfeel and 8.03 for overall acceptability. B₂ had scores of 7.9 for colour, 7.9 for flavour, 7.85 for texture, 7.75 for taste, 7.95 for mouthfeel and 7.94 for overall acceptability. B₂H₂ achieved the highest scores with 8 for colour, 8.1 for flavour, 8.25 for texture, 8.15 for taste, 8.22 for mouthfeel and 8.01 for overall acceptability. These results indicate that B₂H₂ is superior in flavour, texture and overall acceptability.
 
Physico-chemical and microbial analysis of fresh lassi
 
The physicochemical and microbial analysis of selected lassi variants B0, B2 and B2H2 revealed significant compositional differences Table 2. It is clearly seen that addition of Barnyard millet and replacement of sugar with honey caused significant decrease in TSS (15.03 to 12.50oBx), acidity (0.88 to 0.76%), carbohydrates (14.77 to 11.93%), calories (101.37 to 90.99Kcal), whereas significant increase in pH (3.81 to 4.93), proteins (2.52 to 2.92%), fibres (0.08 to 0.67%), ash (0.67 to 0.89%), total solids (21.47 to 22.26%), viscosity (337.33 to 343.25 cP), reducing sugars (4.12 to 8.19 mg/100 g), total phenolics (6.07 to 15.72 mgGAE/100 g) and anti-oxidant activity (4.65 to 9.36 mg/100 g). There was non-significant effect on fat content. B2H2 uniquely contained detectable ascorbic acid (1.45 mg/100 g) due to presence of honey. Similar results were reported in the literature (Shuwu et al., 2011; Pardhi et al., 2014; Khupse et al., 2017). The results also indicated significant increase in total viable count of lassi samples (8.25 to 8.45 log cfu/ml) suggesting that barnyard millet and honey influenced microbial growth. Yeast, mold and coliform counts were not detected in any samples, indicating no fungal or faecal bacteria contamination. These findings align with previous studies by Chick et al., (2001); Krishna et al., (2019); Patel et al., (2020).


 
Shelf-life study of dietetic lassi
 
The shelf-life study of dietetic lassi focused on monitoring its quality and stability over time, examining critical parameters during refrigerated storage (5±2^oC) in conjugation with effectiveness of packaging materials viz. glass bottles, PET bottles and LDPE pouches.
 
Change in sensory analysis during storage
 
During the shelf-life study of dietetic lassi, sensory properties were analyzed and shown in Table 3. There was a significant decline in the scores of samples for all the sensory parameters under acceptable limits like colour (8.50 to 6.50), flavour (8.70 to 6.80), texture (8.00 to 6.00), taste (8.60 to 6.40) and overall acceptability (8.45 to 6.53). Spoilage of lassi samples packed in LDPE pouches was observed indicating less efficiency of package. Among the other samples, lassi stored in glass bottles showed better retention of overall sensory scores (7.13) compared to that of PET bottles (6.53) indicating high efficiency of the package to store lassi under acceptable condition up to 15 days. These findings found to be consistent with previous studies by Patidar and Prajapati (1998); Satkar et al., (2013); Kulthe et al., (2018a) and Ahuja et al., (2017) who reported similar impact of both storage conditions and packaging materials on sensory quality of product during storage.


 
Physico-chemical analysis of dietetic lassi during storage
 
During the shelf-life study of dietetic lassi, TSS, acidity, pH and consistency were monitored shown in Table 3. Initially, the TSS of the lassi at day 0 was 12.50^oBx but decreased notably during storage in glass bottles (10.75^oBx), PET bottles (9.75^oBx) and LDPE pouches (10.75^oBx before spoilage occurred). This reduction in TSS reflects the consumption of sugars, likely due to microbial fermentation (Ding and Shah, 2008). There was significant increase in acidity of samples (0.76 to 1.18%) with decrease in pH (4.93 to 3.53) across all packaging types, indicative of ongoing fermentation and the production of lactic acid and other organic acids (Patidar and Prajapati, 1998 and Bagal et al., 2007). Moreover, consistency increased during storage, indicating changes in the physical properties of the lassi, likely influenced by the conversion of lactose to lactic acid and subsequent protein denaturation, as noted by Amrinder (2018) in a similar context with aloe vera juice incorporated lassi.
 
Microbial analysis of dietetic lassi during storage
 
During the shelf-life study of dietetic lassi, microbial analysis revealed significant changes in the total viable count (TVC) and yeast and mold counts Table 3. Initially, the TVC was 8.40 log cfu/ml but over 15 days, decreased slightly in glass bottles (8.09 log cfu/ml), with more significant reduction in PET bottles (7.73 log cfu/ml) and LDPE pouches (7.98 log cfu/ml). Yeast and mold count initially was not detected but appeared in LDPE pouches (1.87 log cfu/ml) at 5 days, indicating higher susceptibility to contamination compared to that at 15 days in glass bottles (1.62 log cfu/ml) and PET bottles (1.75 log cfu/ml). Similar results were reported in the literature. Patel et al., (2020) reported a decrease in TVC in amaranthus flour incorporated lassi. Sharma et al., (2016) reported an increase in yeast and mold count during the storage period of synbiotic lassi containing honey, with a significant decrease in LAB during storage.

The study on process standardization of Barnyard millet honey blended dietetic lassi involved the physicochemical analysis of milk, Barnyard millet and honey, revealing distinct nutritional profiles. The antioxidant capacity of the Barnyard millet-honey blended lassi (B₂H₂) was measured, yielding an impressive value of 67.8%. Ascorbic acid content was determined to be 12.4 mg/100 g, reflecting the lassi’s enhanced nutritional profile. The reducing sugar content was quantified at 8.2 g/100 g and the total phenolic content was 34.6 mg GAE/100 g, underscoring the lassi potential health benefits due to its high antioxidant and phenolic compounds.
       
Shelf-life studies assessed the stability and quality of dietetic lassi under refrigerated conditions using different packaging materials (glass bottles, PET bottles and LDPE pouches). Results indicated that glass bottles provided the best preservation of sensory attributes, total soluble solids, acidity, pH and consistency over 15 days, while LDPE pouches were the least effective. The microbial analysis showed significant differences in total viable counts, with the highest counts in the B₂H₂ variant, suggesting enhanced microbial growth with the addition of Barnyard millet and honey.

The present study was supported by MIT Art, Design and Technology University, Pune.
 
Disclaimers
 
The views and conclusions expressed in this article are solely those of the authors and do not necessarily represent the views of their affiliated institutions. The authors are responsible for the accuracy and completeness of the information provided, but do not accept any liability for any direct or indirect losses resulting from the use of this content.

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.