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ThesisItem Open Access Standardisation and quality evaluation of banana based probiotic fermented food mixtures(Department of Home Science, College of Horticulture, Vellanikkara, 2010) Sharon, C L; KAU; Usha, VThe study entitled “Standardisation and quality evaluation of banana based probiotic fermented food mixtures” was undertaken with the objective to standardise indigenous food mixtures based on banana flour with probiotic fermentation with Lactobacillus acidophilus and to evaluate the nutritional factors, organoleptic qualities and storage stability of the food mixtures. Probiotic characteristics like acid and bile tolerance and antimicrobial activity of L.acidophilus MTCC 447 showed an acid tolerance ranging from pH 2.0 - 9.0 , a bile tolerance of three per cent and antagonistic activity against enteropathogens viz Salmonella enteritidis, E.coli, Bacillus cereus and Staphylococcus aureus. The foods selected for developing the probiotically fermented food mixtures were banana (Nendran), defatted soya flour, green gram flour, ripe mango, papaya and tomato. From the 56 combinations tried, 14 fermented food mixtures with L. acidophilus MTCC 447 were selected statistically by applying Kendall’s coefficient of concordance. All the 14 selected food mixtures contained 60-70 per cent banana flour, 20 per cent defatted soy flour / green gram flour and 10-20 per cent fruit pulps. For all the treatments variables of fermentation were optimised as 25g of the food mixture (substrate), pH 4.5, inoculum 300µl (119 x 106 cfu /ml), temperature of incubation 37 ºC and time of incubation 24 hours. All the fermented foods along with unfermented controls were freeze dried. Constituents like titrable acidity (2.59 g lactic acid / 100g), protein (7.82g/100g), iron (6.48mg/100g), thiamine (0.0726 mg/100g) and riboflavin (0.535 mg/100g) were significantly high in fermented food mixtures. in vitro digestibility of starch (82.109 per cent) and protein (85.85 per cent) were also significantly high in fermented food mixtures. Total viable count of L. acidophilus ranged from 9.13 to 9.46 log cfu/g. Mean score of overall acceptability of fermented products were between 7.9-8.0 in a 9 point hedonic scale. From 14 fermented food mixtures, six fermented food mixtures were statistically selected considering all the quality aspects by geometric mean score. The selected food mixtures T1, T2, T3, T7, T8 and T9 along with their respective controls were packed in metallised poly ester / poly ethylene laminate pouches and kept for storage studies under ambient conditions for a period of six months. From the six fermented food mixtures with maximum shelf life qualities, three fermented food mixtures were statistically selected by applying geometric mean score. The treatments with maximum geometric mean score were T1 (70 per cent banana flour, 20 per cent defatted soy flour, 10 per cent mango), T3 (60 per cent banana flour, 20 per cent defatted soy flour, and 10 per cent tomato pulp) and T8 (60 per cent banana flour, 20 per cent defatted soy flour,10 per cent mango and 10 per cent tomato pulp).In all the selected three treatments, viable count of L.acidophilus ranged from 8.84 to 9.12 log cfu/g after six months of storage. This viable count was within the desired level of probiotic organisms recommended Substrate composition was modified by adding sucrose, sorbitol, wheat bran and skimmed milk powder to T1, T3 and T8.The level of these four ingredients were standardised as five per cent in T3, with maximum viable counts of L.acidophilus ranging from 9.45 to 9.54 log cfu/g. Thus five treatments (T3 + sucrose 5 %, T3 + 5% sorbitol, T3 + 5% wheat bran and T3 + 5 % skimmed milk powder) was subjected to quality evaluation and shelf life studies. After modifying the substrate, food mixture T3S (with added sucrose at 5 per cent level) showed high acceptability and an increase in the viable count of L.acidophilus after storage, when compared to T3 (control).T3SB (with added sorbitol at 5 per cent level) was comparable to that of T3 (control) in any aspect. T3W (with added wheat bran at 5 per cent level) was also comparable to T3 (control) but with an increase in the total viable count .T3SK (with added skimmed milk powder at 5 per cent level) showed an increase in all the nutrients, acceptability and viable counts. Hence, these four food mixtures (T3S. T3SB, T3 W and T3 SK) can also be recommended as good probiotic food mixtures. The viable count of L. acidophilus in the developed probiotic food mixtures at the expiry period (after six months of storage) ranged between 95 to 210 x 107 cfu/g and in five grams the viability ranged between 475 to 1040 x 107 cfu. This was within the recommended level of the probiotic organism to assure health benefits. Since the fermented food mixtures were slightly acidic in taste, it can be used with acidic foods like buttermilk, fruit juices etc to enhance their acceptability. The cost of the developed food mixtures ranged between Rs 530 to Rs 550 for 400 grams.ThesisItem Open Access Standardisation and quality evaluation of tempeh and tempeh based instant soup mixes(Department of the home science, College of Horticulture, Vellanikkara, 2011) Lakshmy, P S; KAU; Usha, VThe study entitled “Standardisation and quality evaluation of ‘Tempeh’ and tempeh based instant soup mixes” was undertaken with the objectives of standardising the fermented food tempeh with green gram, cowpea, soybean, rice and wheat, and to evaluate its quality attributes. The study also aims to evaluate the nutritional and shelf life qualities of tempeh flour, to develop instant soup mixes with tempeh flour and quality evaluation of these products. Tempeh fermentations were carried out with pure cultures of Rhizopus oligosporus – MTCC 556 and twenty different combinations of selected legumes and cereals were used as substrates. Among the different fresh tempeh types prepared, T1 (100% soybean) had good appearance and texture. The treatments with green gram had a comparable texture and appearance with the control (T1). Tempeh types with rice had better appearance and texture than that of wheat. The overall acceptability of tempeh chips prepared with different combinations of fresh tempeh types ranged from 6.9 to 8.9 with the highest overall acceptability score for T2 (100% green gram) and the highest overall acceptability of roast ranged from 7.5 to 8.9 with the highest score for T11 (cowpea 50% + rice 50%). The highest IVSD of 82.83 per cent was for T9 (green gram 50% + rice 50%) and the highest IVPD of 88.98 per cent was for T8 (green gram 75% + rice 25%). Fresh tempeh types T2 (green gram 100%), T8 (green gram 75% + rice 25%), and T9 (green gram 50% + rice 50%) were selected based on their acceptability, IVSD and IVPD for further studies. T1 (100% soybean) was selected as control. Among the selected fresh tempeh types, the treatment T1 (control) had the maximum moisture (55.85%), protein (21.09%), total fats (10.12 g/100g), β carotene (331.85 µg/100g), thiamine (0.31 mg/100g), calcium (149.10 mg/100g), iron (3.6 mg/100g), phosphorus (270.61 mg/100g) and zinc (2.17 mg/100g) content, whereas the treatment T2 (100% green gram) had the highest fiber (2.52 g/100g), reducing sugar (2.01 g/100g), total sugar (4.21 g/100g) riboflavin (0.30 mg/100g) and potassium (525.11 mg/100g) content. Starch content was highest (29.13 g/100g) in T9 (green gram 50% + rice 50%). None of the selected fresh tempeh types had vitamin C. Mineral availability was found to be very high in the three tempeh types (T2, T8 and T9) compared to the control (T1). The availability of calcium (61.77%), iron (66.82%), phosphorus (65.72%), potassium (63.60%) and zinc (88.99%) was highest in T9 (green gram 50% + rice 50%). None of the tempeh types showed viability at low pH (1.5 to 2.5), bile acid tolerance (1-4 % level) or antibacterial activity against enteropathogens and hence no probiotic activity can be attributed to any of the selected fresh tempeh types. The appearance, colour, flavour and texture of the fresh tempeh types stored under refrigerated condition were satisfactory up to 12 days for T1 (100% soybean tempeh) and T2 (100% green gram). In T8 (green gram 75% + rice 25%) and T9 (green gram 50% + rice 50%), the shelf life was only up to 6 days of refrigerated storage. Frozen tempeh types were comparable to the fresh tempeh even after 30th day of storage. A gradual reduction in the overall acceptability score of the chips and roasts was observed with the stored tempeh types. The bacterial load in the fresh tempeh was found to be high, in the range of 49.3 to 69.3 x 108 cfu/g. A gradual decrease in the bacterial count was observed in all the treatments up to the 6th day of refrigerated storage and thereafter there was a slight increase in the bacterial count. No pathogenic bacteria were identified in fresh tempeh types. The total yeast count in the fresh tempeh types was in the range of 42.6 to 66.3 x105 cfu/g with the maximum in T9 (green gram 50% + rice 50%). A decrease in the yeast count was observed on storage in T1 and T2, but in T8 and T9, there was an increase in the total yeast count on the 9th and 12th day of refrigerated storage which resulted in the spoilage of these tempeh types. The only identified fungus in fresh tempeh types were Rhizopus oligosporus. The total fungal count was in the range of 2.6 to 5.3 x 106 cfu/g in fresh tempeh types which was reduced to 1.0 to 2.3 x 106 cfu/g on the 12th day of refrigerated storage. In frozen tempeh types, the bacterial count was reduced to 0.17 to 0.49 x 108 cfu/g, yeast count to 0.46 to 0.86 x 105 cfu/g and fungal count to 0.06 to 0.1 x 106 cfu/g after 30 days of storage. The flours prepared from the tempeh types were packed in metalised polyester laminate pouches and stored for a period of six months under ambient conditions. The tempeh flours were evaluated for its quality and shelf life attributes. The tempeh flour prepared with T1 had the highest protein (43.15 g/100g), total fats (20.87 g/100g), calcium (331.25 mg/100g), iron (8.03 mg/100g), phosphorus (601.36 mg/100g) and zinc (4.82 mg/100g). Maximum fiber (3.30 g/100g), riboflavin (0.03 mg/100g) and potassium (979.68 mg/100g) were observed in tempeh flour prepared with T2. Starch content was found to be highest (49.38 g/100g) in T9 (green gram 50% + rice 50%). Thiamine was not detected in any of the tempeh flours. A decrease in the protein, total fats, riboflavin, and minerals was observed on storage but were not significant. The highest IVPD of 90.86 per cent after storage was for T8 (green gram 75% + rice 25%) and highest IVSD of 83.86 per cent was for T9 (green gram 50% + rice 50%). All the tempeh flours remained within the prescribed limit of microbial load making them microbiologically safe even after six months of storage. Insect infestation was not observed in tempeh flours during storage. Tempeh flours were used for standardising instant soup mixes with suitable blending materials. For each of the selected tempeh flour (T1, T2, T8 and T9), four different compositions of soup mixes viz. S1(50), S2(55), S3(60), S4(65) were developed, the number in brackets indicating the percentage of tempeh flour used. The soup mixes (16 numbers) were packed in metalised polyester laminate pouches and stored for a period of six months under ambient conditions. The soup mixes were evaluated for quality and shelf life attributes. After storage, the moisture content of soup mixes varied from 6.53 to 7.53 per cent. The nutrients ranged from 5.53 to 34.65 g/100g (protein), 16.67 to 51.45 g/100g (starch), 0.40 to 2.83 g/100g (fiber), 0.67 to 17.93 g/100g (total fats), 0.00 to 0.028 mg/100g (riboflavin), 39.96 to 298.60 mg/100g (calcium), 1.12 to 5.17 mg/100g (iron), 227.61 to 551.66 mg/100g (phosphorus), 432.31 to 961.51 mg/100g (potassium), and 2.11 to 4.42 mg/100g (zinc) in different compositions of soup mixes. Water required for cooking the instant soup mixes to a soup of acceptable consistency varied from 1280 to 1530 ml/100g and the cooking time of the instant soup mixes varied from 3-6 minutes. The mean score for overall acceptability of the soups prepared with the stored soup mixes ranged from 7.5 to 8.2. The overall acceptability score of the soups were lowest in compositions S4(65) with all the tempeh flours. The microbial load in all the soup mixes after storage was within the prescribed limit and all the soup mixes can be considered as microbiologically safe even after storage of six months. Insect infestation was not observed in any of the soup mixes. The cost of production of 1 kg of fresh tempeh types varied from Rs. 57.00 to Rs. 68.00, 1 kg tempeh flour varied from Rs. 111.00 to 142.00 and that of soup mixes (50g) varied from Rs. 12.00 to 13.00.