EFFECT OF LACTIC ACID FERMENTATION OF CASSAVA ON FUNCTIONAL AND SENSORY CHARACTERISTICS OF FUFU FLOUR

The effects of lactic acid fermentation of cassava on the functional and sensory characteristic of fufu flour were investigated. Two strains of Lactobacillus plantarum were used as starter cultures for the fermentation of cassava to fufu for 96   h. The resultant wet fufu samples were dried at 65C in a cabinet dryer for 48   h, and were analyzed for functional and sensory characteristics.
Fermentation reduced the water-binding capacity of the fufu flour from 176.6% to between 118 and 125%. The pasting characteristics of the traditional and starter culture-fermented fufu flour samples were not significantly different from that of the unfermented cassava flour. When subjected to sensory evaluation, the traditional and starter culture-fermented cassava fufu flour were not significantly different in terms of color, odor and texture, but the cassava fufu flour produced, using starter culture SL19, had the highest overall acceptability ( P <  0.05).

PRACTICAL APPLICATIONS

Traditionally, processing of cassava to fufu is usually carried out by using the old stock from a previous fermentation to initiate the fermentation of a new batch. This old method usually results in fufu that has a strong odor that may not be acceptable to some consumers. The use of starter culture like Lactobacillus plantarum will reduce the strong odor of fufu ; this will increase its acceptability by consumers and ensure the overall quality. Also, the functional properties of fufu are not affected. The development of lactobacilli strains could help in optimizing the traditional processes, therefore increasing the economic returns.     

Phytate content is reduced and β‐glucanase activity suppressed in malted barley steeped with lactic acid at high temperature

The effect of different steeping conditions on phytate, β‐glucan and vitamin E in barley during malting was studied by a full factorial experiment with three variables (steeping temperature, barley variety and steeping additions). Addition of lactic acid to the steeping water induced a reduction of phytate during steeping and germination, especially in combination with the high steeping temperature (48 °C). Furthermore, lactic acid and high temperature steeping inhibited β‐glucanase development, resulting in a well‐preserved β‐glucan content after germination. When steeping was conducted without addition of lactic acid, the low steeping temperature (15 °C) promoted development of both phytase and β‐glucanase activity during germination. A slightly higher level of tocopherols and tocotrienols was observed in samples steeped at 15 °C than in samples steeped at 48 °C. However, addition of lactic acid reduced the amount for both temperatures. When lactic acid bacteria were added to the steeping water none of the parameters studied differed from samples steeped with water only. The results show the possibility of combining phytate degradation with a preserved β‐glucan content during malting and can thus be of interest for development of cereal products with improved nutritional value. Copyright © 2004 Society of Chemical Industry     

Microbiological Qualities of Hawked Retted Cassava Fufu in Aba Metropolis of Abia State

Retted cassava fufu samples obtained from five local government areas in Aba Metropolis were analyzed. Their microbial counts, chemical and organoleptic properties were determined from the day of preparation and every day for the eight days of hawking. There were increases in the microbial counts from initial average of 2.02 × 10⁵ cfu/g on the zero day to an average counts of 18.70 × 10⁵ cfu/g on the eighth-day. The microorganisms associated with spoilage were found to be Bacillus cereus, Staphylococcus aureus, Escherichia coli, Candida albicans and Aspergillus spp. The chemical qualities as determined on the freshly prepared fufu samples from all the local government areas were comparable. The colour, odour and texture of the freshly prepared samples were acceptable and rated high by the panelists. It was observed that as the days of hawking of the fufu samples increased, the organoleptic qualities decreased. The pH increased from an average of 3.85 on the zero day to 4.25 average on the eighth day. The titratable acidity decreased from 1.14% on the zero day to 0.94% on the eighth day. The results are discussed in relation to the public health implications of hawked retted cassava fufu.     

Microbiological studies on cassava fermentation for ‘lafun’ production

The microorganisms involved in the traditional fermentation of cassava for ‘lafun’ production were investigated. The microorganisms isolated during the fermentation include Bacillus sp., Leuconostoc sp., Klebsiella sp., Corynebacterium sp., Lactobacillus sp., Candida sp., Aspergillus sp., and Geotrichum sp. The moulds disappeared within the first 36h of fermentation. Bacillus sp. which were present at the beginning of fermentation decreased drastically as fermentation progressed. The yeasts appeared between 24–48h of the fermentation and increased rapidly. The lactic acid bacteria were implicated throughout the duration of the fermentation. Bacillus sp., Corynebacterium sp., Candida sp. and the lactic acid bacteria were considered to play important roles. The titratable acidity of the steeping water and tubers increased rapidly reducing the pH to below 4·0. The temperature of the steeping water varied between 30–32°C and usually not above the ambient. The moisture content of the fermenting tubers increased from 65% to 70% within the first 36 h and was never below 60% during the steeping period. The post-fermentation sun-drying reduced the moisture content to 12–15%.     

Cyanide detoxification in cassava for food and feed uses

Cassava (Manihot esculenta Crantz) is an important tropical root crop providing energy to about 500 million people. The presence of the two cyanogenic glycosides, linamarin and lotaustralin, in cassava is a major factor limiting its use as food or feed. Traditional processing techniques practiced in cassava production are known to reduce cyanide in tubers and leaves. Drying is the most ubiquitous processing operation in many tropical countries. Sun drying eliminates more cyanide than oven drying because of the prolonged contact time between linamarase and the glucosides in sun drying. Soaking followed by boiling is better than soaking or boiling alone in removing cyanide. Traditional African food products such as gari and fufu are made by a series of operations such as grating, dewatering, fermenting, and roasting. During the various stages of gari manufacture, 80 to 95% cyanide loss occurs. The best processing method for the use of cassava leaves as human food is pounding the leaves and cooking the mash in water. Fermentation, boiling, and ensiling are efficient techniques for removing cyanide from cassava peels.     

花生醋浸过程中蛋白质、多酚及其抗氧化性的变化

研究了山西老陈醋浸渍过程中花生蛋白质、多酚含量及其抗氧化性的变化.结果表明,花生在醋浸过程中,粗蛋白、可溶性蛋白含量显著降低,浸泡结束分别降低了32％和41％左右;多酚含量的变化较为复杂,但总体上呈降低趋势,而多肽含量在陈醋浸渍过程中呈增加趋势,其多肽质量分数增加了40.8％.在醋浸前期花生多酚提取物对DPPH、ABTS自由基的清除能力显著增加,在浸渍第10天,花生多酚提取物对DP-PH、ABTS自由基的清除能力分别增加了69.5％和95.3％,而到浸渍后期趋于稳定.     

Processing Techniques to Reduce Toxicity and Antinutrients of Cassava for Use as a Staple Food

ABSTRACT: Cassava is a valuable source of food for developing countries, but it contains highly toxic cyanogen compounds and antinutrients. Cyanogens are found in 3 forms in cassava: cyanogenic glucoside (95% linamarin and 5% lotaustratin), cyanohydrins, and free cyanide. Different processing techniques exist to remove cyanogens and their effectiveness depends on the processing steps and the sequence utilized, and it often is time‐dependent. Pounding or crushing is the most effective for cyanogenic glucoside removal because it ruptures cell compartments, thus allowing direct contact between linamarin and the enzyme linamarase that catalyzes the hydrolytic breakdown. Crushing and sun‐drying cassava roots made into flour removes 96% to 99% of total cyanogens, whereas soaking and sun‐drying into lafun or fufu, or soaking and fermenting and roasting into gari or farina, removes about 98% of cyanogens. For cassava leaves, which have 10 times more cyanogens than roots, pounding and boiling in water is an efficient process to remove about 99% of cyanogens. Other strategies to reduce toxicity include development of low‐cyanogen cassava varieties and cassava transgenic lines with accelerated cyanogenesis during processing. Although phytate and polyphenols have antioxidant properties, they interfere with digestion and uptake of nutrients. Fermentation and oven‐drying are efficient processing methods to remove phytate (85.6%) and polyphenols (52%), respectively, from cassava roots. Sun‐drying the leaves, with or without prior steaming or shredding, removes about 60% phytate. Cassava is a nutritionally strategic famine crop for developing countries and, therefore, reducing its toxicity and improving its nutritional value is crucial.     

Effect of Gamma Rays on Corn Grains. Part III. Effect of Post-Irradiation Storage on Some Technological Properties of Corn Grains and Fatty Acids

The effect of storage after irradiation of corn grains on steeping process, starch isolation, quality of by-products and fatty acids composition of germ oil was investigated. It was found that post-irradiation storage led to a decrease in water absorption and protein solubilization during steeping process. The starch yield was lower, contained a high percentage of protein and was darker from above 500 Krads. Post-irradiation caused a change in the proportions and disappearance or induced new fatty acids in the corn germ oil.     

Processing of Cassava Starch for Adhesive Production

The processing of cassava (Manihot utilissima Pohl) root IITA variety TMS 50395 into starch by varying the steeping period and the effect of these processing methods on the suitability of cassava starch produced for adhesive formulation were investigated. Out of the three processing methods, the one without steeping gave the best starch for adhesive production in terms of the physico-chemical properties such as swelling power. pH, cooking properties, yield, ease of extraction and cost of starch processing. 20% Potassium hydroxide were found to produce the best adhesive product based on the total solids content, pH, colour and applicability.     

EFFECTS OF FINAL WARM WATER STEEP AND AIR REST CYCLES ON MALT PROPERTIES OF THREE IMPROVED NIGERIAN SORGHUM CULTIVARS

The effects of final warm steeping at 40°C and air-rest cycles on malting loss and other malt quality parameters of three improved Nigerian sorghum cultivars were investigated. Grains were steeped for 48 h under four different steep regimes then germinated for 4 days at 30°C. The effect of final warm steeping on kernel growth, malting loss, diastatic power, α and β-amylase and extracts of the malts was significantly affected by air-resting, cultivar and the pair-wise interactions of cultivar and steep regime. Generally, malting loss and kernel growth reduced significantly (p< 0.001) when the steep cycle was a combination of air-resting and final warm water steep at 40°C. Diastatic power, α-amylase, β-amylase and extract also improved significantly in both ICSV 400 and KSV 8 when these grains were malted by a steep regime which combined both air-rest cycles and final warm water steep. However steeping these grains under a final warm water steep without air-resting led to a decrease in extract recovery and enzyme activity. Conversely steeping SK 5912 by a combination of air-resting and final warm water steep generally, inhibited rather than enhanced extract and enzyme development.     

红葡萄浸渍特性的研究

研究了黑比诺、美乐和赤霞珠在浸渍发酵及贮存后花色素的变化规律，结果表明，花色素在浸渍过程中先升高，然后降低，在浸渍的3－4d，且比重低于1．025时可达到最大值，贮存后，花色素的含量明显降低，但随着浸渍时间的处长所表现的变化规律保持不变。     

Traditional and novel fermented foods and beverages from tropical root and tuber crops: review

Tropical root and tuber crops [cassava, sweet potato, yams, colocasia (taro), etc] are important staples for food security for about a fifth of the world population. Bulk of cassava in Africa and Latin America are processed into fermented foods and food additives such as organic (acetic, citric and lactic) acids, mono-sodium glutamate, etc. The fermented foods from cassava are gari , fufu , lafun , chickwanghe , agbelima , attieke and kivunde in Africa, tape in Asia and ' cheese ' bread , and ' coated peanut ' in Latin America. Lactic acid bacteria and yeasts are the major group of micro-organisms associated with cassava fermentation. Similarly, sweet potatoes can be fermented into soy sauce, vinegar, lacto-juices, lacto-pickles and sochu (an alcoholic drink produced in Japan), and yams into fermented flour. Most of these fermented food products are functional foods rich in phytochemicals, dietary fibres, anti-oxidant compounds (β-carotene, anthocyanin, etc) and probiotic components (lactic acid bacteria and yeasts).     

THE DISTRIBUTION OF WATER IN GERMINATING BARLEY

During germination, the embryo of barley absorbs water initially from the film surrounding the corn and later from the endosperm. If growth is stimulated during steeping, absorption of water by the embryo modifies the pattern of moisture distribution and this is usually associated with reduced extractability in the final malt.     

Varietal influence of cassava on chemical composition and consumer acceptability of gari

Effects of cassava variety on chemical composition and consumer acceptability of gari were investigated. Three traditional cassava varieties Bonoua 2, Yace and Yavo as well as four improved cassava varieties Bocou 1, Bocou 2, Bocou 3 and TMS (2) 1425 were evaluated. All the varieties had appreciable high value of carbohydrates ranged from 86.6% (TMS (2) 1425) to 90.89% (Bonoua 2). TMS (2) 1425 had the lowest reducing sugar value (0.22%) while Bocou 3 had the highest reducing sugar value (0.38%). Studied gari exhibited low value of hydrogen cyanide with the lowest value found in Bocou 1 (1.53 mg per 100 g). Total fibre value varied to 2.88% (Yace) to 2.28% (Bocou 2). Gari of Bocou 1 and Bocou 3 were the most appreciated. These gari had fairly sweet taste, were fairly bright and contained few impurities. This study demonstrated that cassava variety influenced the chemical composition and consumer acceptability of gari.     

A Model for Predicting the Effects of a Steeping Program on the Germination of Barley with Different Water Sensitivities

A method for modelling and simulation of malting barley during and after steeping was developed. The modelling was based on data from laboratory scale experiments with various steeping programs. The developed model takes into account the steeping program with different wet steep and air rest periods, the average moisture content of the grains, and the water sensitivity of the raw material, malting barley. The model can be used for the analysis of steeping and the subsequent germination process and for planning of the steeping programs for achieving homogeneous germination in malting.     

Textural changes during cooking of cassava (Manihot esculenta Crantz) roots

Consumer acceptability of cassava food products depends mostly on the final texture of the cooked tissue. The age of the roots at harvest seems to be an important factor in determining the final texture. Two cassava cultivars harvested at 8, 17 and 30 months after planting were used for texture loss determination by a puncture test after cooking at constant boiling water temperature. Kinetic data were analysed using fractional conversion. The raw tissue showed decreasing or constant peak yield force values as the root aged. There was a gradual first‐order softening during cooking, with decreasing rate constant as the root aged. Copyright © 2004 Society of Chemical Industry     

Biochemisch-technologische Studien über die Naßverarbeitung von Mais. 2. Mitt. Die Veränderung der Quellwasserzusammensetzung während des Quellprozesses

Biochemical-Technological Studies on Wet-Processing of Maize. Part 2. The Change in the Composition of Steeping Water During the Steeping Process. 1. The time, for which the steeping water stays in a countercurrent steeping battery of 8 tanks, is about 20 h and should not be regarded as the steeping time of maize. 2. The changes in the composition of steeping water (dry matter, SO₂ content, nitrogen substances, reducing substances, mineral substances, lactic acid) have been examined in the normal technological steeping cycle (without interruption of maizemilling), during the 40–50 hours' milling break as well in a laboratory-one-tank system, and from this resulting indications as to the processes taking place within the maize grain have been obtained. From the interior of the grain, substances that have become soluble by secondary reactions (SO₂, enzymes) get into the steeping water beside substances that have been present in soluble form from the very start.     

纤维素酶对玉米淀粉生产中浸泡效果的影响

本研究通过使用纤维素粗酶制剂对湿法生产玉米淀粉的浸泡工艺的影响进行了研究,结果表明,纤维素粗酶制剂能够显著地缩短玉米淀粉生产的浸泡时间,降低了二氧化硫的使用浓度,在0.1%的二氧化硫浓度的浸泡液中添加0.3%纤维素粗酶制剂,作用时间为12h,其淀粉得率为57.0%,而使用传统的逆流法工艺(实验室模拟)浸泡48h的淀粉得率仅为54.1%。     

Effect of consecutive steeping on antioxidant potential of green,oolong and black tea

After water, tea is considered to be one of the most consumed drinks worldwide. To get the maximum benefit from the whole‐leaf teas, the manufacturers provide instruction that these teas can be steeped 2–3 times over 6–8 h. In this study, the effect of consecutive steeping on radical‐scavenging ability of whole leaf green tea (unfermented), oolong tea (partially fermented) and black tea (fully fermented) was determined. Green tea showed the highest level of antioxidant activity, total phenolic and flavonoid content followed by oolong tea and black tea irrespective of the number of steeping done. The result also demonstrated that re‐steeping reduced the antioxidant potential of teas. Moreover, it was revealed that green tea is the best candidate for re‐steeping followed by oolong and then black tea.