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العنوان
MICROBIOLOGICAL STUDIES ON SOME
FERMENTED FOODS \
المؤلف
ALI, SHIMAA ABDEL RAUOF AMIN.
هيئة الاعداد
باحث / SHIMAA ABDEL RAUOF AMIN ALI
مشرف / Abdel Mohsen Ahmed Refaat
مشرف / Hemmat Mohamed Abdelhady
مناقش / Hemmat Mohamed Abdelhady
تاريخ النشر
2014.
عدد الصفحات
226p. :
اللغة
الإنجليزية
الدرجة
ماجستير
التخصص
علوم وتكنولوجيا الأغذية
تاريخ الإجازة
1/1/2014
مكان الإجازة
جامعة عين شمس - كلية الزراعة - مكروبيولوجيا زراعية
الفهرس
Only 14 pages are availabe for public view

from 226

from 226

Abstract

SUMMARY
Fermented food represent on average one-third of total food consumption (Nout and Kiers, 2005) especially fermented soybean that are wide-spread from many part of the world as a local food. Soybean and soybean products containing various amounts of phenolic compounds have been shown to posse’s antioxidative activity. So, these products are considered to have potential role in preventing chronic diseases such as cancer, atherosclerosis, osteoporosis and menopausal disorder. The optimal conditions for fermented soybean products are known to be quite different. In Egypt, studies concerning for the manufacture of these products are limited and it is not produced on large scale. In view of these facts, the present work was achieved to evaluate studies were focused on:
1- Microbiological, chemical and sensory evaluation of some manufactured soybean product such as natto , miso and tempeh.
2- Use of some raw legume seeds for tempeh production by solid state fermentation.
3- Studying factors affecting on the fermentation of soybean tempeh by Rhizopus oligosporus ATCC 22959.
4- Evaluation of fermented tempeh during different storage periods at different temperatures.
5- Using the mixed culture from yeast and LAB to improve the antioxidant level and nutritional quality of ferment soybean tempeh .
6- Improvement the nutritional quality of okara (waste soybean manufacturing products) by microbial solid state fermentations.
7- Biological evaluation of fermented soybean tempeh and okara using animal experiments.
The results could be summarized as follows:
1- Manufacture and evaluation of some soybean fermented foods.
Soybean tempeh and natto were manufactured from dehuled
socked cooked soybean by Rhizopus oligosporus ATCC 22959 and
SUMMARY
Shimaa A. Amin, Ph.D., 2013
Bacillus subtilis nattoATCC 21332 using solid state fermentation process. These products in addition to commercial miso were used to study their microbiological, chemical and sensory characteristics.
• Natto recorded the lowest count of aerobic mesophilic bacteria, total staphylococcoi, yeast and fungi. Tempeh product contains the total staphylococcoi, yeast and mold higher than miso , where the vice versa was true for aerobic mesophilic bacteria . All products were free from E.coli, Staphylococcus aureus and salmonella group.
• The highest values of moisture and ash were noticed in miso (49.4% & 4.34%) followed by natto (44.5% & 2.40%) and tempeh (38.4% & 2.25%). The tempeh product contained the amount of nitrogen%, protein% and amino acids higher than other products, whereas the vice versa was ture for total carbohydrates %. Although the natto contains the amount of protein higher than miso product, the latter recorded the higher total amino acids. The highest values of antioxidant compounds as indoles and phenols were produced in miso followed in natto and tempeh being 180.4 & 242.8 mg/100g , 161.0 & 215.5 mg/100g and 125.3 & 164.1 mg/100g dry weight, respectively. Also, the antioxidant activities of these products gave the same trend.
• The highest score of appearance (8.7), Color (8.5), Texture (8.1), Taste (7.1) and overall acceptability (6.4) were recorded by tempeh product. Whereas miso product recorded the highest score of odar and mouth feeling being 6.9 and 6.2, respectively. Natto gave the lowest value for all sensory characteristics.
2- Evaluation of tempeh prepared from some legumes.
Dehulled soybean, faba bean , chickpea , lupine and cowpea seeds were used for tempeh preparation by Rhizopus oligosporus ATCC 22959 using solid state fermentation technique .
• The chemical composition of tested seeds was differed from one to another. The highest protein and lipid contained was observed in
SUMMARY
Shimaa A. Amin, Ph.D., 2013
soybean followed by faba bean seeds being 38.8 and 37.18%, respectively. Whereas raw chickpea, lupine and cowpea seed recorded the higher carbohydrate content ranged from 60.4 to 69.83% and lowest protein content ranged from 23.46 to 25.04%.
• In the manufactured tempeh , the moisture % , protein% and amino acids (mg/100 g dry weight ) were increased , whereas the ash% and lipid % were decreased comparing to raw seeds content .
• Moreover, the content of tempeh from anti-nutritional factors ( phytic acid% and tannins mg/100g dry weight ) were decreased while the antioxidant substances as indols and phenols as well as antioxidant inhibition activities were increased. The lowest values of phytic acid (0.27%)& tanines (51.6 mg/100 g dry weight ) were presented in cowpea and soybean tempeh , respectively. The latter product also, recorded the highest indoles (161 mg/100g), phenols (215.5 mg/100g) and antioxidant inhibition activity.
• The deep-fried tempeh was more susceptible than blancing tempeh. The highest score of the most sensory characteristics was recorded by deep-fried soybean, faba bean and chickpea tempeh recorded the highest score of appearance (8.7) whereas the second product gave the highest score of texture (8.2), odor (7.9) and mouth feeling (8.5) as well as the third product gave the highest score of taste and overall acceptability (8.5).
3- Factors affecting on tempeh manufacture.
A- Effect of some pretreatments
• All different soaking period (from 6 to 30 hr) were not affected in the final tempeh products.
• Different cooking period ranged from 30 to 60 min were studied. The optimum period was found to be 30 min for soaked soybean & faba bean and 50 min for soaked chickpea.
• Two crush periods for 30 & 60 sec were tested. Uncrushed treatment was more suitable for soybean tempeh whereas bean
SUMMARY
Shimaa A. Amin, Ph.D., 2013
crushed for 30 sec was the best treatment for faba bean and chickpea tempeh .
B- Using pellet or mat inocula of Rhizopus oligosporus ATCC 22959 failed on the manufacture of tempeh, whereas using spore inoculation with 104 spore /g raw seeds at 7 days age was the best method of inoculation.
C- Four degree of temperature being 25, 30, 35&40°C were tested . The optimum temperature for good quality of soybean, faba bean & chickpea tempeh was 30°C. Increasing the fermentation temperature for 40˚C resulting in the failure of process.
D- Different fermentation periods (1 - 96 hr) were studied. The optimum fermentation period was found to be after 72 hr , as it gave the log number cfu/g of total aerobic mesophilic bacteria , staphylococci , yeast and mold were 9.94, 7.81, 9.61 and 7.34 for soybean tempeh and 10.94, 6.60, 9.48 and 8.41for faba bean tempeh
• During the fermentation period , the moisture%, ash% , lipid % & total carbohydrates% were decreased whereas the nitrogen% and protein% were increased to record the lowest or highest figures at 72 hr fermentation period, respectively. At this peiod the fermented tempeh contains the highest amino acids content which increased about 2.25&1.8 folds than control for soybean and faba bean tempeh, respectively. Also, the fermentation decreases the anti-nutritional constituents (as phaytic% and tannins) and increasing the antioxidant inhibition activity as well as antioxidant compounds (phenol and indoles).
E- The effect of storage period on fresh tempeh was studies during 8 weeks at room and refrigerator temperatures.
• At the end of storage period of both treatments, the log number of aerobic mesophilic bacteria, total staphylococci, yeast and fungi increased about 11 %, 17 %, 12 % and 8 % as compared with that presented before storage, whereas the log number of mould decreased about 5.8%.The percentage of total Staphylococci increasing at
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126
refrigerator temperature after 4 weeks (19 %) was higher than at room temperature after 8 weeks (13 %), whereas the vice versa was true for increasing the mould count after 4 weeks. Also, coliform bacteria that are found in samples were non-fecal coliform. In tempeh either before or after storage Staphylococcus aureus could not be found.
• The nitrogen, protein and ash were decreased whereas the lipid content increased in the samples storage at room temperature but little or not change was observed in the samples which storage in refrigerator.
• The amount of amino acids was higher at refrigerator temperature than room temperature and ranged from 265.1 to 281.6 mg/100g. and from 100 to 276.8 mg/100g., respectively. The inhibition activity (%) of soybean tempeh increased during the first fourth weeks to reach 20.6% and 39.12% at room temperature, respectively. At refrigerator temperaure, the phytic acid and phenol content decreased from 0.49 to 0.34% and from 213.3 to 204.4 mg/100g., respectively, whereas the indols value was constant during the storage period. The tannins increased from 80 to 118.3 mg/100g and from 46.9 to 80 mg/100g at room and refrigerator temperature, respectively.
4. Soybean tempeh manufacture by mixed culture.
Three different treatments of co-cultivation were used to ferment the soybean seeds inoculated with Rhizopus oligosporus ATCC 22959 these treatments were Lactobacillus acidophilus ATCC 11975 co–cultivation, & Saccharomyces cerevisiae ATCC 58523 co-cultivation and Lactobacillus acidophilus ATCC 11975 & Saccharomyces cerevisiae ATCC 58523 co-cultivation. The tested strains of yeast and LAB could grow together with Rhizopus oligosporeus during soybean tempeh fermentation and that their growth neither reduced fungal growth in tempeh, nor did they change the appearance of final products.
SUMMARY
Shimaa A. Amin, Ph.D., 2013
• At co-cultivation with Lactobacillus acidophilus ATCC 11975, the log number cfu/g of mesophilic bacteria, Lactobacilli, total staphylococci and yeast recorded the highest value at the end of fermentation period whereas the log number of fungi was constant during the fermentation. At co-cultivation with Saccharomyces cerevisiae ATCC 58523 and the co-cultivation with both strains, the lowest content of mesophilic bacteria and total staphylococci was recorded at the end of fermentation period. Whereas the log number of yeast count was decreased during the fermentation of the first treatment and was constant at the second treatment. The log count of fungi was slightly decreased during the fermentation period for both treatments. Lactobacilli count was detected only at the second treatment. All tempeh products of these treatments were free from Staphylococcus aureus, total coliform, E. coli, and Salmonella group.
• During the fermentation period, the moisture % and ash % were decreased, whereas nitrogen % and protein % were slightly increased. The highest figures were recorded at co-cultivation with both Lactobacillus acidophilus ATCC 11975 and Saccharomyces cerevisiae ATCC 58523 fallowed by that mixed with Saccharomyces cerevisiae ATCC58523 and by mixed with Lactobacillus acidophilus ATCC11975 treatment, respectively.Whereas the co-cultivation with Saccharomyces cerevisiae ATCC 58523 gave the highest amino acids content (280.2 mg/100g) fallowed by co-cultivation with both Lactobacillus acidophilus ATCC 11975 and Saccharomyces cerevisiae ATCC 58523 (272.1 mg /100g) and by co-cultivation with Lactobacillus acidophilus ATCC 11975 (235.1 mg /100g).
• At the end of fermentation period, indoles and phenols of fermented tempeh were ranged from 152.4 to 157.2 (mg/100g) and from 201.1 to 219.8 mg/100g dry weight, moreover the maximum figures were recorded at co-cultivation with Saccharomyces cerevisiae ATCC 58523 treatment. Whereas the lowest figures of anti-nutritional factors (phytic acid% &
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tannins mg/100g) were recorded at co-cultivation with mixed Lactobacillus acidophilus ATCC11975 and Saccharomyces cerevisiae ATCC58523 treatment (28.5 mg/100g & 0.65%) fallowed by co-cultivation with Saccharomyces cerevisiae ATCC58523 (34.2 mg/100g & 0.72%) and co-cultivation with Lactobacillus acidophilus ATCC11975 treatment (40.5 mg/100g & 0.86%).
• No significant differences (P > 0.05) in appearance, color, texture and taste characteristies was observed between all tested mixed cultures. Also, these treatments recorded the higher score of mouth feeling (6.0 & 6.0) and overall acceptability (7.6 &7.4) than fermentation by Rhizopus oligosporus ATCC 22959 alone or by Rhizopus oligosporus ATCC 22959 co-cultivation with Lactobacillus acidophilus ATCC 11975 (5.3 & 6.1).
5. Fermentation of soybean okara.
• The fermentation of okara was carried out by three different yeast strains Saccharomyces cerevisiae ATCC 58523, Kluyveromyces lactis ATCC 8585, Saccharomycopsis sp and B.subtilis ATCC 6633 strain for 72 hr at 30˚C.
• The highest log count of fermented strain was recorded by B. subtilis ATCC 6633 followed by Saccharomycopsis sp
• The highest nutritional quality and antioxidant activity of fermented okara were obtained by Saccharomyces cerevisiae ATCC 58523. where it increased the protein, amino acids, phenols and indoles about 49.7%, 47.5%, 23.4% and 24.1%, respectively, and reduced the phytic acid and taninnes about 52.8% and 58% as well as increased the antioxidant activities about 3.08 fold.
6. Biological evaluation.
Four groups albino mouse were fed on raw soybean, soybean tempeh, fermented okara and mixed fermented okara and soybean tempeh 1:1 (w/w) in order to study their effect on weight of vital organs and
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blood constituents of rats. The percentages of Packed cell volume (%),
Haemoglobin (g /dL), Red blood cells (10P
6
P mm3) and white blood cells
(10P
6P mmP
3P) which include neutrophils (%), lymphocytes (%), basophiles
(%) and eosinophils (%) of rate fed on (group 2) tempeh had the higher
parameters compared to the other groups., Total serum protein (g/dl) of
rats fed with raw soybean (group1) recorded the highest value (8.37)
whereas albumin/globulin ratio (A/G) was the lowest value. Also, it could
be noticed that group 4 (rates fed with tempeh and okara) gave the values
of PCV, Hb and RBC higher than group 3 (rates fed with fermented
okara). Also, the liver weight was heavy in group 4. Which recorded the
highest protein digestibility being 79% and increased the protein
efficiency ratio from 2.87 to 3.17. So, it could be recommended to use the
mixture from soybean tempeh and fermented okara for animal feeding as
low cost feeding which more suitable than fermented okara only.