Applications of Biotechnology in Traditional Fermented Foods (1992) / Chapter Skim
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IV. PLANT DERIVATIVES
IV. PLANT DERIVATIVES
Pages 87-118
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From page 89... ...
Submerged fermentation involves the soaking of whole peeled, cut and peeled, or unpeeled cassava roots in water for various periods, as typified by the production of fufu and lalun in Nigeria. Traditionally, cassava is fermented for 4 to 6 days in order to The support of the International Foundation for Science, Stockholm, Sweden, is gratefully acknowledged.
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From page 90... ...
A microbial succession trend was found with the starch degrading Bacillus subtilis, giving way to the lactic acid bacteria and yeasts that dominate the latter part of the fermentation. The pH and titratable acidity of the fermenting cassava roots increased from 6.3+0.2, 0.08+0.03 percent to 4.0+0.3, 0.36+0.05 percent, respectively, after the 96-hour fermentation period.
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From page 91... ...
· Appropriate starters have been developed that can produce amylase and linamarase enzymes necessary for starch breakdown and cyanogenic glucoside hydrolysis; two major biochemical processes needed in cassava processing. For this, the lactic acid bacteria were investigated since they were the predominant microbial group present at the beginning of fermentation and which persist and survive the acidic conditions that prevail in cassava fermentation.
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From page 92... ...
Genetic manipulation of the starter culture offers the best hope for improved cassava processing, with higher economic returns and improved stable qualities. Cassava processing could also be enhanced by using biotechnological principles to modify structural and processing characteristics of cassava cultivars to meet specific product requirements.
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From page 93... ...
Yet it is nutritionally inferior to maize, which is deficient in certain essential amino acids, because of the maize-milling process that is an integral part of ogi production. Cassava, another very important food crop, has the problem of possible nutritional complications because it contains the cyanogenic glucosides linamarin and lotanstralin.
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From page 94... ...
CYANIDE REDUCTION DURING CASSAVA PROCESSING Two foods processed from cassava (gari and ijapu) were studied.
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From page 95... ...
95 -~o _ C~ Cal In on ~5 U)
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From page 96... ...
TABLE 1 Cyanide Content of Cassava During Processing into Ijapu Cyanide Content (ppm) Material analyzed pH Total Free HCN Bound Cyano Unprocessed peeled cassava 6.3 76.1+15.3 5.5+2.2 2.9+0.4 70.6 2.6 Boiled cassava Boil water "Ijapu" (after 24 hours steeping)
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From page 97... ...
Yet a substantial proportion of the linamarin in cassava was still lost, appearing to a large extent in the water used for boiling and for steeping (Tables 1 and 2~. This would suggest that leaching could be an important factor in cyanide loss during cassava processing.
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From page 98... ...
1979. Enzymatic assay for determining the cyanide content of cassava and cassava products.
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From page 99... ...
1983. Some flavoring constituents of cassava and of processed cassava products.
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From page 100... ...
, or soybean Hour have been used to raise protein levels in such feeds, but these products raise the price of feed significantly. To upgrade the protein content in maniac, yeast cells or fungi can be inoculated in a manioc-containing medium along with nutrients containing nitrogen, phosphorus, and potassium.
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From page 101... ...
The maximum protein content was attained in medium containing urea (4 percent) and ammonium sulfate (5.8 percent)
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From page 102... ...
Manioc pieces of 0.5 to 1.0 centimeters are best for this solid fermentation method. The protein content of fermented preparation decreased 50 percent when using manioc pieces that were 1.0 to 2.0 .
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From page 103... ...
TABLE 6 Product Analysis Fermented Manioc Pieces Preparation, N° Index Culture-Medium, Percent Percent 1 Protein 1.5-2.0 10.0-13.3 Starch 33 11 Reduce sugar 4.4 8.11 Total sugar 8.4 13.00
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From page 104... ...
104 CONCLUSION FERMENTED FOODS This solid-state fermentation method can be used to upgrade by six to seven times the protein content in manioc pieces. The resulting fermented product contains 10 to 13 percent protein, which is suitable for use as a feed additive.
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From page 105... ...
In each case, fermentation yields a product that is not only organoleptically acceptable but also sufficiently highly regarded nutritionally by the local people to be employed as a meat substitute. As the sun-dried food can be stored indefinitely without deterioration, these fermentation processes represent a food preservation technique particularly well suited to the climate and conditions of this part of Africa.
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From page 106... ...
PROTEIN CONTENT AND QUALITY The crude protein content decreased only slightly, if at all, during fermentation of each substrate, indicating little loss of nitrogen during
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From page 107... ...
CHANGES DURING FERMENTATION The dominant role of lactic acid and the marked decrease noted in pH during the sigda fermentation contrast strongly with the high concentrations of volatile fatty acids (VFA) and minimal pH change observed in the kawal fermentation (Table 3 and Figure 1~.
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From page 110... ...
obtusifolia leaves, which possess approximately double the calcium content of sesame seedcake. Conditions in kawal do not, therefore, favor the selection of acidoduric lactic acid bacteria.
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From page 111... ...
111 (ma t_600L 6)
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From page 112... ...
Further investigation of the furundu fermentation would be most instructive in this respect. CONCLUSIONS The sigda and furundu fermentations appear quite unlike the traditional oilseed fermentations practiced in Nigeria and elsewhere in West Africa where foods such as ogili and ogiri are fermented from castor oil seed (Ricinus communist and melon seed (Citrullus vulgarisJ.
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From page 113... ...
The three fermentations studied appear to afford a route by which unpalatable plant material or oilseed cake of little economic value can be converted into acceptable meaty-tasting food that is particularly rich in sulphur amino acids, which tend to be deficient in diets where access to meat or fish is limited. Phytic acid present in seeds can frequently hinder absorption of minerals in the gastrointestinal tract.
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From page 114... ...
Over time the soybeans and wheat are hydrolyzed by enzymes such as proteinases, peptidases, and amylases. During the first stage of moromi fermentation, Pediococcus halophilus grows and produces lactic acid, which lowers the pH.
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From page 115... ...
. (n c o Go o 115 Bioreactor Method I Defatted I [Wheat | I Soybean I ' I Steam Roast Hydrolysis and Fermentation Lactic Acid and Alcohol Fermentation Aging Culture LContinuous culture Broth I of KoliMold Hydrolysis (40° to 50°C for 3 days)
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From page 116... ...
versatilis was about 1 ppm, which is the optimum concentration in conventional soy sauce. The total residence time for lactic acid and alcohol fermentation was about 30 hours in this system.
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From page 117... ...
6.0 4.0 The organic acids and aroma components in the bioreactor soy sauce were examined. The proportions of organic acids except citric acid were not much different between the bioreactor soy sauce and the conventional one, although the former was a little lower in acetic acid and succinic acid.
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From page 118... ...
The total time required for the production of soy sauce by the bioreactor system, including enzymatic hydrolysis of the raw materials, fermentation with immobilized whole cells, and the refining process, is only about 2 weeks (24. This is considerably shorter than the 6 months with the conventional method of soy sauce brewing consisting of koji making, fermentation and aging of moromi, and refining.
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