Development of Gulabjamun with Incorporation of Foxtail Millet

In the current millennium, the dairy market is experiencing a transition from bulk commodities to delightfully tasty and novel value-added goods, with a distinctive niche segment in taste, colour and appearance. Value added food items have taken on significant importance nowadays.
       
Gulabjamun is a sweet indigenous commodity, commonly prepared from khoa in the country’s northern, western, and central regions. It is usually prepared by kneading wheat flour (maida) and baking powder with cow or buffalo milk khoa to form smooth dough, portioning the dough, rolling it into balls of spherical shape, deep frying the balls in oil until they turn golden brown in color and soaking them in the sugar syrup overnight Nalavade et al. (2015). The texture of gulabjamun is largely assessed by its textural attributes such as sponginess and juiciness, with crumbliness and gumminess being the main undesirable attributes (Ghosh et al., 1986, and Patel et al., 1992).  
       
Millets are known as food security crops owing to their sustainability under adverse agro-climatic conditions (Ushakumari et al., 2004). The richness in calcium, dietary fiber, polyphenol and protein contents in millets make them unique among the cereals (Bhat et al., 2018). Smaller millets like finger millet have been used in value-addition of products like cookies (Sinha and Sharma, 2017).
       
Foxtail millet (Setaria italica L.) is a significant minor millet that is also known as Italian millet, German millet, Siberian millet and Bristle grass foxtail. The seeds are convex in shape, oval or elliptical, light yellow to brown, rusty or black. It continues to occupy a significant role in world agriculture, providing around six million tons of food to millions of people, primarily on poor or marginal soils in Southern Europe and in temperate, subtropical and tropical Asia (FAOSTAT, 2005). It is nutritionally superior to rice and wheat, and thus provides the population dependent on these grains with proteins, minerals, and vitamins (Tylor and Emmanbux 2008).
       
A combination of milk product (gulabjamun) and millet (foxtail) in the present scenario has synergistic effect, where, deficiency of lysine in foxtail millet and deficiency of dietary fibre and iron in milk product are being complemented by each other. Thus, the present study was undertaken to develop value added gulabjamun with foxtail millet for better nutritional profile.
 

The study was carried out in the Department of Food Science and Nutrition, University of Agricultural Sciences, Bangalore, during the year 2019-2020.
 
Procurement of raw ingredients
 
Ingredients like full cream milk, millets, sugar, oil, maida, baking powder and ghee were procured from local markets of Bengaluru.

Development of product
 
Fresh khoa was broken into bits and was kneaded well to a homogenous mass free of lumps. Maida, used as a binding agent was added at 14% and baking powder, used as a leavening agent was added at 1% rate. Foxtail millet flour was added at 20%, 30% and 40% rate based on the weight of khoa. Dry ingredients were first mixed thoroughly prior addition to khoa. Sufficient kneading was done till the dough could easily be rolled into smooth balls. Milk was used to soften the dough to desired consistency. The dough was uniformly rolled into 10 g balls each and were deep fried to golden brown colour and subsequently transferred to 60° Brix sugar syrup maintained at about 60°C. The fried balls were left undisturbed for about 2 hours to completely absorb the sugar syrup. Formulation of gulabjamun is given in Table 1.


 
Sensory evaluation
 
Sensory evaluation was carried out using nine-point hedonic scale. The score card was based mainly on appearance, colour, texture/consistency, taste and overall acceptability.  Twenty-two semi trained judges having good health status and interested in sensory evaluation were selected from Department of Food Science and Nutrition, UAS, Bangalore.
 
Nutritional analysis
 
Moisture, protein, fat, ash and crude fibre content of sensorial best accepted gulabjamun along with control gulabjamun (GJN1) were analyzed using standard methods specified by AOAC. Carbohydrate content of the same was calculated using difference method. Titrimetric method for calcium (Heau et al., 1965), atomic absorption spectrophotometry for iron and liquid chromatography for vitamin A (AOAC, 2001) estimation was employed.
 
Texture analysis
 
Texture profile analysis (TPA) was done using Stable Micro System TAXDi Texture Analyzer fitted with 100 kg load cell. A P36R cylindrical probe was used with 5 mm/s of pre-test, 0.5mm of test and post-test speeds. Representative graphs for the texture of products displayed in the computer attached to the instrument was studied to compute parameters such as hardness, cohesiveness, adhesiveness, springiness, gumminess and chewiness.
 
Shelf life study
 
The product best accepted by the sensory panel along with control gulabjamun was considered for shelf life studies and the changes in sensory characteristics, moisture and microbial load were studied for a period of 15 days. The products were stored in air tight polypropylene containers and studied at room and refrigerated temperature (7°C). The containers were dipped in 0.5 per cent H₂O₂ solution and dried in an oven maintained at 60-65°C for 30 min prior to the study.
 
Data analysis
 
The data was analyzed using one-way analysis of variance (ANOVA) (F-test) and in randomized complete block design to determine the level of significance.Two-way analysis of the variance was applied for microbial population.

Sensory evaluation
 
Mean scores for sensory attributes of foxtail millet incorporated gulabjamun are presented in Table 2. The scores of gulabjamun incorporated with foxtail millet ranged from 8.59 to 8.81 for appearance, 8.58 to 8.59 for colour, 7.82 to 8.68 for texture/consistency, 7.79 to 8.86 for taste and 7.97 to 8.77 for overall acceptability. Control had highest score for all of the sensory characteristics. Sensory scores were observed to decrease with increasing incorporation levels. Among the variations, GJF1 with 20% incorporation levels was found to be best accepted and GJF3 with 40% incorporation levels had the least score. Statistical significance was observed in sensory characteristics like texture, taste and overall acceptability at 5% level. Whereas, appearance and colour showed non-significant difference owing to the reason that each of them were formed into uniform balls and were fried till golden brown colour. A decreasing score was observed in case of texture with increasing levels of millet incorporation. Replacing khoa with millet flour hardened the texture and reduced the sugar syrup absorption.


       
In line with the study, Gulabjamun developed by incorporating Amaranthus hypochondriacus L. (Rajgara) showed the overall acceptability scores ranging from 6.67 to 7.88 on a scale of 10 (Shendurse and Chaudhary, 2020).
 
Nutritional analysis
 
Table 3 presents the nutritional composition of best accepted gulabjamun. Owing to the addition of foxtail millet to gulabjamun, crude fibre and iron content significantly increased (at 5% level) from 0 to 1.12 and 0.58 to 0.702 respectively. Whereas, a significant decrease in fat, protein, calcium and vitamin A content was observed as, per gram availability of these nutrients are higher in khoa than in the millets.


       
The results obtained in the present study are in accordance with those reported by Prajapati et al., (1992), Adhikari et al., (1994), Nalawade et al., (2015) and Chaudhari (2016).
 
Texture analysis
 
Textural profile of best accepted gulabjamun variations is tabulated as in Table 4. It was observed from the results that hardness, cohesiveness and gumminess of gulabjamun increased with addition of foxtail millet; whereas, springiness, adhesiveness and chewiness showed a decreasing trend. However, significant difference among the variations in all of the rheological parameters was observed at 5% levels. It was evident that with addition of millets to gulabjamun, the hardness increased. This increase might be due to the decrease in fat content and reduction in moisture content (Gulhati et al., 1992).


       
Studies conducted by Singh et al., (2009), Ghube et al., (2015) and Yawale and Rao (2012) were in line with the above results.
 
Shelf life study
 
Shelf life study by sensory evaluation
 
Table 5 and 6 represent the effect of storage on sensory scores of gulabjamun at room and refrigeration temperature respectively. The sensory scores of gulabjamun during storage, regardless of storage at room temperature or refrigeration temperature, tend to decrease with the increase in storage period.  Samples had acceptable sensory scores between ‘like very much’ to ‘like extremely’ till 5^th day when stored at room temperature and till 15^th day at refrigeration temperature.




       
During storage, experimental sample of gulabjamun may have undergone various physicochemical and microbial changes, which tends to affect the sensory attributes of the product. The observed decline in overall acceptability of gulabjamun could partly be attributed to development of change in flavour owing to development of flat, insipid taste with slight souring tinge.
       
A similar finding from a study conducted by Chaudhary (2016) showed that at the room temperature (30±2°C) flavour, body and texture, colour and appearance and overall acceptability score of gulabjamun decreased significantly (P<0.05) from 8.83 to 6.4, 8.5 to 6.30, 8.67 to 7.85 and 8.67 to 6.3 respectively while at refrigeration temperature (7±2°C) from 8.83 to 6.43, 8.5 to 6.1, 8.67 to 7.27 and 8.67 to 6.13 respectively.
 
Shelf life study by moisture content
 
Effect of storage on moisture content of gulabjamun at room and refrigeration temperature given in the Table 7 and 8 respectively. Moisture content of gulabjamun samples decreased with increasing storage period. Control gulabjamun had a decrease in moisture from 35.90 to 35.60 by 5^th day when stored at room temperature and to 35.32 by 15^th day when stored at refrigeration temperature. Foxtail millet incorporated gulabjamun (20%) showed a decrease in moisture content from 33.51 to 33.31 by 5^th day at room temperature and to 33.03 by 15^th day at refrigeration temperature. All of the samples at both room and refrigeration temperature showed a significant difference at 5% levels.




       
Similar findings were also observed in a study conducted by Vasava et al., (2018), gluten-free gulabjamun packed in composite polyethylene terephthalate (PET) bottles and stored at refrigeration temperature showed a decrease in moisture from 32.9 to 31.57 by 35^th day of shelf life study.
 
Shelf life study by microbial population
 
Table 9 and 10 show the microbial population of gulabjamun in room temperature at different intervals of storage. BIS specifications for gulabjamun allow a maximum of 2000 cfu/g total bacterial count and 50 cfu/g fungi. The results reported during the study were well within the limits. However, foxtail millet incorporated gulabjamun samples, on storage at room temperature, developed visible mold growth on 6^th day and was observed in control product on 7^th day. Chaudhary (2016) also studied the effect of room and refrigerated storage on microbial population in gulabjamun and results were in accordance with the present study.




       
Therefore, foxtail millet incorporated gulabjamun (GJF1) was acceptable up to 5 days at room temperature and up to 15 days at refrigerated storage.
 

Milk and dairy products are considered as ‘nearly complete’ foods as they contain a wide array of nutrients. However, it is well known that milk is not a good source of iron and fibre. Millets, in contrast, are deficient in essential amino acids like lysine, compromising the protein quality. An effort was therefore made in the present study to formulate food products from milk-millet combination. Results revealed that foxtail millet could successfully be incorporated to a traditional dairy product like gulabjamun, with highly acceptable sensory attributes. Thus, development and consumption of such products from milk-millet combination can be encouraged among all healthy sectors of population and the enhanced nutritional profile can be exploited.