4.1 Effect of processing on ingredients;
Different ingredients like defatted soy flour, green gram, wheat were used for development of protein rich fortified flour after suitably processing (soaking, germination, cooking, blanching and fermentation) for nutritional enhancement and minimization of antinutritional compounds. The effect of processing conditions on different ingredients ware carried out and reported in Table 1. Antioxidant activity of ingredients was found to increase by about 7-8%.The processed ingredients were used for development of protein rich flour as per nutritional/health requirement of children (Fig.1).The major formulations were finalized and multi-flours was prepared by using processed ingredients; soy meal-rice –green gram based Nutritional, rheological, textural, colour, antioxidant, microbiological and functional properties of developed products was evaluated. The protein content of these mixes was found in the range of 18-20%.
Fig.1 compressed protein bar
Table 1. Effect of processing on different ingredients
( Wheat, rice,
green gram etc)
5. Tannin content
6. Phytate content
7. Antioxidant activity
No significant change
Not significant change
Reduce 65 %
Increases (5-7 %)
Formulation of composite flour for preparation of compressed protein bar;
A linear programming model was developed in order to formulate mixtures based on rice, wheat, mung bean, commercially defatted soybean meal, skimmed milk powder and other ingredients at the lowest possible cost and in such a way as to fulfil the protein requirement.
Equations (Constraints) for linear programming
51s + 24g + 8.6r + 34m + 35p + 24v ? 16 (protein)
9s + 8.5g + 1.1r + 2.5m + 0.3p + 28v ? 9 (iron)
240s + 140g + 5r + 415m + 1250p + 2100v ? 600 (calcium)
4.2 Proximate composition of Composite flour
High moisture levels (above 10%) accelerate spoilage by promoting microbial activity and chemical reactions that reduces product shelf life. Sufficient processing of raw materials is critical for proper storage of complementary foods. The protein content of soy meal-rice –green gram based and soy meal-wheat –green gram based composite flour were within the minimum recommended levels of 14% (N X 6.25) by CODEX (2006) for management of malnutrition (Table 2). The protein contents of the composite flour formula were found to be 20 %. Protein recommendation by FAO/WHO and Institute of Medicine (IOM) for normal children is set at 21g/1000kcal. The fat content of both composite flours were slightly higher then prescribed minimum levels of 6% specified by CODEX (2006) for treating moderate malnutrition in children . A child suffering from malnutrition has high-energy needs requiring a diet of sufficient fat content. Fat is also needed in the absorption of vitamins A and E. Vitamins A and E are vital for immediate recovery from acute malnutrition and to reduce disease incidences in children. Milk-based products have been demonstrated to boost children’s growth and immunity associated with fat-soluble vitamins (Diop el et al., 2003). It is desirable that diets contain high fat to provide the required energy to the malnourished child.
Percentage in-vitro protein digestibility of formulated flour was comparable to those of the commonly used complementary foods (Table 3). Protein quality is a measure of the efficiency of utilization of proteins by the body which depends on the amino acid composition, digestibility of the proteins and the biological availability of its amino acids for the synthesis of tissue proteins.The levels of antioxidant activity in both composite flours was 64 %. The levels of protein digestibility in both the formulated composite flours were 81.25 respectively.
Table2. Chemical composition of formulated composite flour for complementary food
(%) Soya based composite flour
Antioxidant activity 64
( cfu/g) Nil
Protein Digestibility (%) 81.25
Fat acidity 0.32
Colour parameters like ‘L’value, ‘a’ (redness/greenness) value, ‘b’ (yellowness/blueness) value and Yellowness Index of the flour formulations were measured and presented in Fig. 2. Addition of banana found to increase the yellowness value of the flours.
4.3 Consumer acceptability
Sensory quality of some of the formulated complementary foods compare to the commonly used complementary foods in the zone was both liked moderately on the hedonic scale. A number of organoleptic features, such as flavour, aroma, appearance and texture, may affect infant’s intake of transitional foods which may results in increased consumption. Feeding infants with improved complementary foods as that formulated in this study for children in the zone may cause improvement in their growth. Rice, wheat, mung bean and soybean meal were properly processed (germination and fermentation). The developed composite flours were used for preparation of various protein rich products like fortified biscuits, protein energy snacks and bars consumer acceptability.
4.4 In vitro protein digestibility (IVPD)
The effect of different heat processing on the in vitro protein digestibility (IVPD) of investigated grains is shown in table 2. There was a difference in IVPD of heat processed ingredients and control. IVPD significantly increased in processed. The improvement of IVPD after heat process is most likely ascribed to destroying the heat labile protease inhibitors and denaturation of proteins, thus opening up their structure and therefore making them less resistant to proteases (Walker and Kochar, 1982). This consequently increases the accessibility of the proteins to the enzymatic attack. This improvement could also be due to the diminution in phytic acid and tannins upon heat treatment. As protein digestibility of
Fig.2 colour analysis of composite flour
grains are influenced by the presence of antinutritive factors (Khattab et al., 2009) different processing and specially dry heat treatment that affect the levels of those antinutritive factors will subsequently influence protein digestibility.
4.5 Preparation of a compressed protein bar
The use of legumes in food improves the overall protein quality as they are rich in essential amino acid lysine. On the other hand, cereal proteins complement legume protein in the essential amino acid methionine. The addition of 10–15% defatted soy flour, soy concentrates and isolates to wheat flour not only significantly improve the quality of protein but also enhances their quantity considerably.Defatted soy flour has been used to develop various nutritious protein rich products such as snacks, baby foods, chapatti, beverage and bread. Effect of protein isolates (Pea and soy bean) have been studied on the functional and rheological properties of protein enriched gluten free composite flour. The nutritious energy bars have gained more importance and popularity in the global market during recent years and today the market is offering wide variety of bars under different names.Indigenously made bars like Horlicks multi cereal nutri bar, Rite bite Chocó delite bars, low fat bar, sugarless bar, woman bar, fruit choco bars etc are gelling popular among Indian consumers.
Chemical composition of developed protein bar is given in table 3.
Table.3. Chemical composition of developed protein bar
Parameters Value (%)
Total fat 23.0
Total sugar 24.00
Total ash 1.65
Antioxidant activity 31.4
Sensory evaluation and storage Sensory evaluation was carried out by trained panel of judges (20 nos.) at 9 point Hedonic scale grading (Table.4).
9 = excellent, like extremely 4 = Dislike slightly
8= Very good, Like very much 3 = Dislike moderately
7 = Good, like moderately 2 = poor, dislike strongly
6= Fair, like slightly 1 = Very poor, dislike extremely
5= Neither like nor dislike
After 5 months of storage, it was observed that there were slight but significant increase in moisture content in PP packaging material but difference in MP stored samples were not significant. Chemical changes in composite cereal bar were found least but significant in samples packed in MP and stored at ambient temperature.
4.6 Sensory evaluation of multigrain bars
Organoleptic evaluation of the amaranth based multigrain bar formulations was undertaken on the basis of sensory characteristics such as colour, flavour, texture, taste and over all acceptability. Thus average score recorded by judges were presented and discussed here as per 9 point hedonic scale in table 4. Flavour and taste were significantly improved by incorporation of milk powder and dry fruit powder. The increase in flavour and taste of the product may be due to development of acceptable pronounced pleasant flavour and taste to grains during roasting. Therefore flavour and taste of the product was greatly enhanced by incorporation of chocolate and milk powder in multigrain bar
Table 4: Sensory scores (9 point hedonic scale) of compressed protein bar
Sample Taste Texture/mouthfeel colour Appearance Overall acceptability
Compressed protein bar 7.5
7.41 8.00 8.65 8.25
Overall acceptability of the protein rich multigrain bar progressively increased with increase in level of fruit rich component in multigrain bar. Incorporation of Choco ball and coconut milk improved the product significantly with respect to colour, flavour, taste, texture and overall acceptability.
4.7 Texture analysis of the compressed protein bars;
A texture analysis is primarily concerned with measurement of the mechanical properties of a product. Texture analyzer performs this test by applying controlled force to the product and recording its response in the form of force, deformation and time. Hardness is the force necessary to attain a given deformation of the material or it is the force required to bite through the sample with molars. Texture in terms of hardness of various multigrain bars viz. protein, mineral and fiber rich multigrain bar along with Experimental control is measured and presented in in fig.3.
Fig 3; Texture analysis of compressed protein bar
• Hardness values were measured in a Texture Analyzer with the help of a cutting blade, and the maximum force required to cut the samples are represented as Hardness
• Developed protein bars and balls have less hardness values than commercially available Nutribar
It is clearly seen that hardness of protein, mineral and fiber rich multigrain bar increased significantly after grain incorporation in protein, mineral and fiber rich multigrain bar. This might be due to grain small size, their compatibility with binding agent, protein and fiber rich ingredient. Similar results observed by Rawat and Darappa (2015) for protein as well as fiber rich ingredient mixture containing bars. Protein rich ingredient mixture bar formulated using wheat, soya protein concentrate, chickpea and sesame flour, whereas fiber rich ingredient mixture bar with mungbean and banana fruit flour. They recorded hardness more in protein based bar than fiber based bar.
Texture of the bar become harder during storage and influenced the overall acceptability scores adversely.The hard texture development in protein rich bar may also be due to the migration of moisture as well as formation of most ordered secondary structure and lower surface hydrophobicity of protein particles. Based on above, compressed protein bar remained shelf stable for 3 months in PP and 4-5 months in MP at ambient temperature and 37°C.
4.8 Colour measurement of Protein rich multigrain bar
Visual quality encompasses the appearance of the product. Colour is a perceptual phenomenon that depends on the observer and the conditions in which the colour is observed. It is a characteristic of light, which is measurable in terms of intensity and wavelength. The colour of a material becomes visible only when light from a luminous object or source illuminates or strikes the surface (Pathare et al., 2013). The colour of the product was measured by the “Hunterlab”. .Mr. Richard Hunter invented the L, a, b colour scale that took the theory that we don’t just “see” colour but we can also talk about how light or dark the object is. +L means the sample is whiter/brighter side, -L means the sample is darker/blackish side, +a means the sample is redish side, – a means the sample is greenish side, +b means the sample is yellowish side and – b means the sample is bluish side.
4.9 Microbiological stability study
Microbial spoilage is often the major factor limiting the shelf life of product. Spoilage from microbial growth causes economic loss for manufacturer and consumer. These losses can be minimized to some extent by adopting desirable packaging material during storage.
In present study multigrain bars were found to be more nutritionally rich with increase nutrient rich Even though sensory evaluation was important as it give prediction related to acceptability by consumers hence compressed protein bars which were more accepted on the basis of sensory evaluation were further utilized for microbial studies during storage.
Total plate count of the most acceptable multigrain bars which were packed in packaging material such as metalized pouch (MP) were studied. These packaged multigrain bars stored at ambient temperature for 3 months to study their microbial safety. Microbial examination was carried at 45 days interval for 180 days and obtained results were expressed as log CFU/g. Microbiological data also indicates the stability of products (table 5.). Metalized pouch packed protein rich multigrain bar showed the minimum growth with respect to total plate count during 180 days of storage.
Table 5. Microbiological parameter of developed products
Attribute Packaging materials Temperature Storage period
Initial 3 months
Microbiology MP (TBC,cfu/g) 250 C 3×101 6×101
MP ( coliform) 250 C ND ND
Effect of packaging material on free fatty acid and peroxide value
Food packaging plays a vital role in determining the shelf life of foods as they act as a barrier for oxygen and loss or gain of moisture in foods (Khan et al., 2008). Selection of a proper packaging material is most essential to ensure maximum product quality during storage to prevent oxidation of lipids (Seacheol and Zhang, 2005). Development of off flavour due to lipid peroxidation in low moisture foods is the major cause of rejection of processed foods by the consumer. Development of off flavour was resulted due to the decomposition of peroxide and formation of volatile adehydes, ketones, esters etc. having low flavour threshold values. Therefore, the rate of lipid peroxidation was monitored by following changes in peroxide value, free fatty acids, in multigrain bar packed in different packaging materials in order to assess their shelf-life.
Effect of packaging materials on the chemical changes in the protein rich multigrain bar at ambient temperature are given in table.6.
It is evident from the data that free fatty acid of the compressed protein bar packed in Metallized Pack was gradually increased during storage irrespective of packaging material. The changes in peroxide value (PV) also followed the same trend. The lower rate of peroxidation found in LDPE samples can be attributed in MP. Similar observation was recorded by Ananthan et al., (2012) for protein rich cereal bar during 9 months of storage in polypropylene, paper-aluminium foil polyethylene laminate, metalized polyester films. They find that free fatty acid and peroxide value were increased in all packaged samples but least changes were observed in metalized polyester sample. Free fatty acid (per cent oleic acid) and peroxide value (per cent) of metalized polyester packed sample after 9 month storage at ambient temperature was from 1.9 and 0.90 to 4.2 and 23.1 respectively. Variation in recorded values of free fatty acid and peroxide in previous research and present work might be due to variation in ingredient and adapted method of preparation.
Table 6. Changes in peroxide value (meq O2 /kg oil) and free fatty acids (%) in soy composite compressed protein bar stored at 25°C and 37°C in Metalized packaging materials
Attributes Packaging materials Temperature Storage period
0 Day 3 Month
FFA (%) MP 250 C 1.6 2.1
MP 370 C – 2.3
Peroxide value MP 250 C 0.83 8.7
MP 370 C – 9.5
These ready-to-eat foods like multigrain bar are most susceptible to lipid oxidation, irrespective of lipid content, acquire considerable flavour and odor, reduce sensory perception of foods during storage and make the food unpalatable. Therefore extension of shelf life and preservation of ready-to-eat foods is of utmost importance. Food packaging plays a vital role in determining the shelf life of foods as they act as a barrier for oxygen and loss or gain of moisture in foods. Selection of a proper packaging material is most essential to ensure maximum product quality and acceptability during storage.