Processing and characteristics of soybean-fortified gari

Two cassava cultivars were fermented for 3 days with the incorporation of soybean residue or full-fat flour at 25% (w/w) to produce gari. Unfortified gari was superior in taste (P<0.05) to the soybean-fortified gari, though consumers still accepted the latter. Fortified samples from two of the three procedures used, in which soybean was added at different stages of the fermentation, were rated similarly (P>0.05). The water activity of soybean-fortified gari was <0.7, the swelling capacity was 2.5 to 3.3, pH was 5.1±0.2 and total cyanide was 0.8 to 1.3 mg/100 g. The crude protein content of soybean-fortified gari was 8 to 12% (w/w), much higher than the 1 to 2% (w/w) of the unfortified gari. Soybean-fortified gari is recommended for use in areas where cassava is consumed and protein intake is inadequate.The authors are with the Biology Department, The Polytechnic, Ibadan, Nigeria.     

Saccharification of cassava peels waste for microbial protein enrichment

Cassava waste peels may constitute up to 55% of the original tuber. These waste peels were found to contain 41.8% carbohydrate, 1.1% protein, 12.5% ether extract and 4.9%, 4.9% total ash. and 20.8% crude fibre. Studies were conducted to formulate a fermentation medium to convert the waste peels to reducing sugars and to enrich the peels with microbial protein. Amylase producing microorganisms were isolated from rotten cassava tuber discs buried in the soil at different locations. The microorganisms isolated were Aspergillus fumigatus, A. flavus, A. niger, and a Pseudomonas sp. and A. niger; the level of reducing sugar was 20.5 mg/ml. The lowest was by B. subtilis an isolate from fermenting locust bean. Generally the levels of saccharification were higher when the waste media were supplemented with different nitrogen sourses. The crude protein yield in the cassava peel waste media by different microorganisms varied from 5.6% to 17.5%. The highest protein yield was in the waste medium fermented by A. fumigatus followed by A. niger, B. subtilis, Pseudomonas sp. in decreasing order.     

Mechanisms of increased linamarin degradation during solid-substrate fermentation of cassava

Several fungi and bacteria, isolated from Ugandan domestic fermented cassava, released HCN from linamarin in defined growth media. In 72 h, a Bacillus sp. decreased the linamarin to 1% of initial concentrations, Mucor racemosus to 7%, Rhizopus oryzae and R. stolonifer to 30%, but Neurospora sitophila and Geotrichum candidum hardly degraded the linamarin. Adding pectolytic and cellulolytic enzymes, but not linamarase, to root pieces under aseptic conditions, led to root softening and significantly lower linamarin contents. Neurospora sitophila showed no linamarase activity, in contrast to M. racemosus and Bacillus sp., both of which were less effective in root softening and decreasing the root linamarin content. The most important contribution of microorganisms to linamarin decrease in the solid-substrate fermentation of cassava is their cell-wall-degrading activity, which enhances the contact between endogenous linamarase and linamarin.A.J.A. Essers and M.H.J. Bennik were and M.J.R. Nout is with the Department of Food Science, Wageningen Agricultural University, Bomenweg 2, 6703HD Wageningen, The Netherlands. A.J.A. Essers is now with the Department of Toxicology, Wageningen Agricultural University, PO Box 8000, 6700EA Wageningen, The Netherlands; M.H.J. Bennik is now with the Agrotechnological Research Institute, PO Box 17, 6700AA Wageningen, The Netherlands.     

Production of ethanol from cassava whey

Investigations were conducted into the potential use of enzyme hydrolysed cassava whey for ethanol production by Saccharomyces cerevisiae Aspergillus niger grown on whct bran was used as crude enzyme source to saccharify the whey starch. The whey with an initial HCN concentration of 54.0μg/ml was fermented at pH 4.5 and 30°C in a one-step process to produce ethanol. A maximum ethanol concentration of 4.5% (v/v) was obtained in 120 h with a decrease in HCN level to 4.0 μg/ml. In a two-stage fermentation, in which the raw whey was pre-hydrolysed and under the same fermentation conditions, the unsterilized hydrolysate yielded alcohol content of 5.5% (v/v), while the sterilized hydrolysate gave higher alcohol yield, 7.5% (v/v), in 48 h. No HCN was detected in the fermented liquour at the end of the two-stage process.     

The influence of narrow-leafed lupin seed fermentation on their chemical composition and ileal digestibility and microbiota in growing pigs

The aims of this study were to provide a controlled fermentation process of blue lupin seeds (Lupinus angustifolius, cv. Neptun), monitor the changes in seed composition and determine the influence of the fermentation on the apparent ileal digestibility (AID) of crude protein (CP) and amino acids in growing pigs, compared with raw lupin seeds. The fermentation with bacteria and yeast was conducted for 24 h at 25ºC under aerobic conditions. Seed fermentation increased the contents of CP, fibre, fat and ash and most of the analysed amino acids but reduced the levels of the nitrogen-free extractives. Furthermore, fermentation decreased the contents of raffinose family oligosaccharides and phytic acids but increased the alkaloid content. The AID was estimated on three barrows (mean initial body weight 25 kg), surgically fitted with a T-cannula in the distal ileum. The pigs received three diets, each for 6 d, within three experimental periods (3 × 3 Latin Square design). The diets contained soybean meal (Group SBM), raw lupin seeds (Group RL) or fermented lupin seeds (Group FL) as solely protein sources. Fermentation had a positive impact on the AID of CP and methionine, cysteine, isoleucine, leucine, phenylalanine and valine (p < 0.05). Feeding raw or fermented lupin seeds did not affect the microbial status of the ileal digesta. Moreover, ammonia content in the caecal digesta did not differ between Groups RL and FL, although it was significantly higher than in Group SBM. It can be concluded that the fermentation process modified the chemical composition of nutrients in seeds, which can influence the digestibility and utilisation of the fermentation product in animal diets compared to raw seeds.     

Enhanced production of raw starch degrading enzyme using agro-industrial waste mixtures by thermotolerant Rhizopus microsporus for raw cassava chip saccharification in ethanol production

In the present study, solid-state fermentation for the production of raw starch degrading enzyme was investigated by thermotolerant Rhizopus microsporus TISTR 3531 using a combination of agro-industrial wastes as substrates. The obtained crude enzyme was applied for hydrolysis of raw cassava starch and chips at low temperature and subjected to nonsterile ethanol production using raw cassava chips. The agro-industrial waste ratio was optimized using a simplex axial mixture design. The results showed that the substrate mixture consisting of rice bran:corncob:cassava bagasse at 8?g:10?g:2?g yielded the highest enzyme production of 201.6?U/g dry solid. The optimized condition for solid-state fermentation was found as 65% initial moisture content, 35°C, initial pH of 6.0, and 5?×?10⁶ spores/mL inoculum, which gave the highest enzyme activity of 389.5?U/g dry solid. The enzyme showed high efficiency on saccharification of raw cassava starch and chips with synergistic activities of commercial α-amylase at 50°C, which promotes low-temperature bioethanol production. A high ethanol concentration of 102.2?g/L with 78% fermentation efficiency was achieved from modified simultaneous saccharification and fermentation using cofermentation of the enzymatic hydrolysate of 300?g raw cassava chips/L with cane molasses.     

Detoxification of cassava by Aspergillus niger B-1

 The effects of fermentation of cassava by Aspergillus niger B-1 β-glucosidase on its cyanide and protein content, and the optimal conditions for this enzyme’s activity, were examined. This fermentation process reduced the cyanide content of cassava by 95% to 2 mg/kg, and increased its total protein content by 50%, thereby improving its nutritional value. A significant decrease in cyanogenic glycosides was detected after 3 days of fermentation. The optimal pH for A. nigerβ-glucosidase activity on the cyanogenic glycoside linamarin was determined to be 3, the optimal temperature 55 °C, and its K _m 0.3 mM. The findings presented here will facilitate the development of an improved method for detoxification of cassava and for enhancement of its nutritional value. Received: 17 August 1995/Received revision: 27 October 1995/Accepted: 30 October 1995     

Nonpungent Capsicum fermentation by Bacillus subtilis and the addition of Rapidase

To reduce the pungency of Capsicum without the loss of its biological activity, a Capsicum sp. was fermented by Bacillus subtilis with the addition of Rapidase enzyme. At 1 day of fermentation, the capsaicin content of the Capsicum ferment with Rapidase had sharply decreased from an initial content of 11.8 to 2.8 μg/ml. The Rapidase-fermented Capsicum had higher total flavonoid and phenolic contents than the Capsicum ferment without Rapidase. In addition, ABTS radical scavenging activity was enhanced in the Rapidase-fermented Capsicum as compared to that without Rapidase. Overall, fermentation using B. subtilis and Rapidase was an efficient method to produce a non-pungent Capsicum with antioxidant properties.     

Modelling of the rate data from the fermentation of cassava slurry

Data from analyses of the fermentation of cassava slurry were used to derive kinetic constants for the rate of hydrolysis of bound cyanide, formation of free cyanide, pH change and fermentation. The pseudo-kinetic constant for the decay of bound cyanide was 1·6 times 10^-2/h and 2·5/h for free cyanide. Under the experimental conditions, the concentration of bound cyanide at any time during fermentation was 22·65e^-0·016tμg/g, where t is time in h. The fermentation rate constant was determined as 2·2871 times 10¹⁹. Based on the empirical expressions of the rate data, it is believed that rate constants of the intrinsic parameters of fermentation of systems similar to cassava slurry could be determined.     

Evaluation of Cyanogenic Potentials of Local Cassava Species and Residual Cyanide Contents of Their Locally Processed Food Products in Southeast Nigeria

The cyanogenic potentials and residual cyanide contents of local cassava parenchyma and their locally processed food products in southeastern Nigeria were studied. Seven species of cassava locally grown and four main food products from them were analyzed colorimetrically for their cyanide contents. Results of the analyses indicated that five of the species contain cyanide potentials between 50 and 100 mg HCN/kg fresh weight while only one contains cyanogens level greater than 100 mg HCN/kg fresh weight. Of the cassava products analyzed, two contained cyanide above the level recommended by the WHO/FAO (10 mg HCN/kg). The result raises concern as these cassava products constitute about 80–90% of the diet of the local people and the facts known about cyanide poisoning from intake of high cyanide containing food.     

甲烷菌对厌氧真菌不同碳源代谢的影响

【目的】探讨碳源和甲烷菌对厌氧真菌碳代谢的影响。【方法】利用体外批次厌氧发酵法,比较厌氧真菌纯培养(Orpinomyces sp.和Neocallimastix sp.)及其与甲烷菌共培养(F1:Orpinomyces sp.+Methanobrevibacter sp.和N3:Neocallimastix sp.+Methanobrevibacter sp.)发酵不同类型碳水化合物代谢产物的差异。【结果】对厌氧真菌和甲烷菌共培养F1和N3的研究显示,F1发酵木薯粉[(26.44±0.22)mmol/L]的乳酸产量是发酵玉米芯[(1.31±0.04)mmol/L]的20.18倍,是N3发酵木薯粉[(1.59±0.03)mmol/L]的16.63倍,玉米芯[(0.79±0.08)mmol/L]的33.47倍。当F1和N3中的厌氧真菌纯培养时,各组乳酸产量均1.90 mmol/L。对F1进一步研究,结果显示发酵体系中木薯粉添加量在0.8%–2.0%之间时,乳酸产量随木薯粉添加量增加而增加。当含量在1.0%–2.4%之间时,随木薯粉添加量增加,甲烷和乙酸产量逐渐降低。比较F1发酵大米粉、木薯粉、玉米粉、小麦粉和土豆粉的发酵结果,发现乳酸产量与底物中支链淀粉的含量成正相关(R2=0.9554)。当F1发酵葡萄糖和麦芽糖时,乳酸产量5.00 mmol/L。当以麦芽糊精为底物时,乳酸产量高达(28.00±0.95)mmol/L。【结论】本文首次报道碳源和甲烷菌能够增强厌氧真菌的乳酸代谢途径并且这种增强存在种属特异性。     

Direct fermentation of raw starch using a Kluyveromyces marxianus strain that expresses glucoamylase and Alpha‐amylase to produce ethanol

Raw starch and raw cassava tuber powder were directly and efficiently fermented at elevated temperatures to produce ethanol using the thermotolerant yeast Kluyveromyces marxianus that expresses α‐amylase from Aspergillus oryzae as well as α‐amylase and glucoamylase from Debaryomyces occidentalis. Among the constructed K. marxianus strains, YRL 009 had the highest efficiency in direct starch fermentation. Raw starch from corn, potato, cassava, or wheat can be fermented at temperatures higher than 40°C. At the optimal fermentation temperature 42°C, YRL 009 produced 66.52 g/L ethanol from 200 g/L cassava starch, which was the highest production among the selected raw starches. This production increased to 79.75 g/L ethanol with a 78.3% theoretical yield (with all cassava starch were consumed) from raw cassava starch at higher initial cell densities. Fermentation was also carried out at 45 and 48°C. By using 200 g/L raw cassava starch, 137.11 and 87.71 g/L sugar were consumed with 55.36 and 32.16 g/L ethanol produced, respectively. Furthermore, this strain could directly ferment 200 g/L nonsterile raw cassava tuber powder (containing 178.52 g/L cassava starch) without additional nutritional supplements to produce 69.73 g/L ethanol by consuming 166.07 g/L sugar at 42°C. YRL 009, which has consolidated bioprocessing ability, is the best strain for fermenting starches at elevated temperatures that has been reported to date. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:338–347, 2014     

Microbial population and biochemical changes during production of protein-enriched fufu

Summary Candida utilis strain BKT4 and Saccharomyces cerevisiae strain BKT7 isolated from burukutu (a local wine brewed from sorghum) were used to enrich fufu. During the fermentation process, there were changes in the microbiological and biochemical characteristics of the cassava. The total viable counts increased with increasing fermentation time while the counts of the lactics and fungi increased at the later stages of the fermentation due to the acidity of the medium. Various bacteria (Bacillus, Staphylococcus, Klebsiella, Escherichia, Streptococcus, Lactobacillus, Leuconostoc, Corynebacterium), moulds (Penicillium, Aspergillus, Fusarium, Mucor, Rhizopus) and yeasts (Candida, Saccharomyces, Hansenula, Rhodotorula) were found to be associated with the fermentation process. The pH of the fermenting cassava increased from 4.2 to 5.7 after 72 h while the cyanide level decreased from 2.2 mg/kg to 0.7 mg/kg over the same period of fermentation. Fufu (prepared by crushing and sieving fermenting cassava roots) enriched with 0.5 g of C. utilis strain BKT4, S. cerevisiae BKT7 and a mixed culture of the two organisms revealed a crude protein of 7.90, 6.34 and 10.0% respectively as compared to 2% protein content of the enriched fufu. There was a corresponding increase in protein content of the product as the quantity of the enrichment yeast was increased from 0.5 to 3.0 g. The aroma of the enriched fufu was preferred to that of the commercial fufu. Generally, good acceptability and organoleptic qualities (colour, taste, texture and aroma) of the protein enriched fufu was best achieved within 48 h of enrichment. The results of this study suggest that fufu can be made more nutritious with yeasts particularly Candida utilis strain BKT4 and Saccharomyces cerevisiae strain BKT7.     

A catalogue of some ecuadorean fermented beverages,with notes on their microflora

Summary A catalogue of indigenous fermented beverages produced by different ethnic groups in Ecuador has been compiled and the microflora of selected examples examined. A diversity of fermentation substrates was encountered depending on the climatic zone. The fermentations are typicallyLactobacillus spp.—yeast fermentations except for one which includes a mould fermentation by a mixed starter ofMoniha sitophila, Rhizopus stolonifer and aFusarium sp. A discussion is made of the role of these beverages in the human ecology of certain regions.

---

Resumen Se ha confeccionado un catálogo de bebidas indígenas ecuatorianas producidas por distintos grupos étnicos, examinándose la microflora de algunos ejemplos seleccionados. Las fermentaciones son generalmente del tipoLactobacillus sp.—levaduras, excepto en un caso que incluye una fermentación fúngica iniciada de forma mixta porM. sitophila, R. stolonifer y unFusarium sp. Se discute el papel de estas bebidas en la ecologia humana de ciertas regiones.

---

Résumé Un catalogue des boissons fermentées indigènes produites par divers groupes ethniques de l'Equateur a été compilé et les micro-flores des exemples sélectionnés ont été éxaminés. Les substrats de fermentation varient d'une région climatique à l'autre. Les fermentations sont généralement du typeLactobacillus sp — levures, sauf dans un cas qui comporte une fermentation par des moisissures, avec un mélange initial deMoniha sitophila, Rhizopus stolonifer et une espèce deFusarium. Le rôle de ces boissons dans l'écologie humaine de certaines régions est discuté.

     

Experiences with the use of a starter culture in the fermentation of maize for ‘kenkey’ production in Ghana

Controlled fermentation of maize was carried out using six strains of Lactobacillus fermentum and one strain of yeast, Saccharomyces cerevisiae, isolated from traditionally fermented maize dough as starter cultures for inoculum enrichement. The fermentations were monitored by pH, acidity, microbiological analysis and taste panel evaluation of two products, kenkey and koko, prepared from the fermented doughs. The strains of L. fermentum used as starter culture dominated the microflora during fermentation and in most inoculated doughs the required pH was attained by 24 h instead of 48 h of dough fermentation. Higher contents of lactic acid bacteria and yeasts were observed in inoculated doughs at the initial stages of fermentation but the spontaneously fermented doughs attained similar lactic acid bacteria and yeasts counts by 24 h of dough fermentation. The organoleptic quality of kenkey and koko prepared from doughs fermented with starter culture for 48 h was not significantly different from the traditional products. Kenkey prepared from doughs fermented for 24 h with starter culture were found to be unacceptable by the taste panel although similarly produced koko was acceptable.The authors are with the Food Research Institute, Council for Scientific and Industrial Research, P.O Box M 20. Accra, Ghana.     

Production of ethanol from raw cassava starch by a nonconventional fermentation method

Raw cassava root starch was transformed into ethanol in a one-step process of fermentation, in which are combined the conventional processes of liquefaction, saccharification, and fermentation to alcohol. Aspergillus awamori NRRL 3112 and Aspergillus niger were cultivated on wheat bran and used as Koji enzymes. Commercial A. niger amyloglucosidase was also used in this experiment. A raw cassava root homogenate–enzymes–yeast mixture fermented optimally at pH 3.5 and 30°C, for five days and produced ethanol. Alcohol yields from raw cassava roots were between 82.3 and 99.6%. Fungal Koji enzymes effectively decreased the viscosity of cassava root fermentation mashes during incubation. Commercial A. niger amyloglucosidase decreased the viscosity slightly. Reduction of viscosity of fermentation mashes was 40, 84, and 93% by commercial amyloglucosidase, A. awamori, and A. niger enzymes, respectively. The reduction of viscosity of fermentation mashes is probably due to the hydrolysis of pentosans by Koji enzymes.     

Cassava as a Cheap Source of Carbon for Rhizobial Inoculant Production using an Amylase-producing Fungus and a Glycerol-producing Yeast

Summary The aim of this research was to develop methods to use low-cost carbon compounds for rhizobial inoculant production. Five raw starch materials; steamed cassava, sticky rice, fresh corn, dry corn and sorghum were tested for sugar production by an amylase-producing fungus. Streamed cassava produced the highest amount of reducing sugar after fermentation. Bradyrhizobium japonicum USDA110, Azorhizobium caulinodans IRBG23, Rhizobium phaseoli TAL1383, Sinorhizobium fredii HH103, and Mesorhizobium ciceri USDA2429 were tested on minimal medium supplemented with reducing sugar obtained from cassava fermentation. All strains, except B. japonicum USDA110, could grow in medium containing cassava sugar derived from 100 g steamed cassava per litre, and the growth rates for these strains were similar to those in medium containing 0.5 (w/v) mannitol. The sugar derived from steamed cassava was further used for production of glycerol using yeast. After 1 day of yeast fermentation, the culture containing glycerol and heat-killed yeast cells, was used to formulate media for culturing bradyrhizobia. A formulation medium, FM4, with a glycerol concentration of 0.6 g/l and yeast cells (OD₆₀₀ = 0.1) supported growth of B. japonicum USDA110 up to 3.61 × 10⁹ c.f.u./ml in 7 days. These results demonstrate that steamed cassava could be used to provide cheap and effective carbon sources for rhizobial inoculant production.     

Yeast diversity in rice-cassava fermentations produced by the indigenous Tapirapé people of Brazil

The Tapirapé people of the Tapi'it?wa tribe of Brazil produce several fermented foods and beverages, one of which is called 'cauim'. This beverage usually makes up the main staple food for adults and children. Several substrates are used in its production, including cassava, rice, corn, maize and peanuts. A fermentation using rice and cassava was conducted, and samples were collected at 4-h intervals for microbial analysis. The yeast population was low at the beginning of the fermentation and reached 6.9 x 10(7) CFU mL(-1) after 48 h. During the fermentation process common yeast species were identified by sequencing of the D1/D2 domain of the large-subunit (26S) rRNA gene. The predominant yeast species found was Candida tropicalis. Candida intermedia, Candida parapsilosis, Pichia guilliermondii, Saccharomyces cerevisiae and Trichosporon asahii were also found in high numbers during the fermentation. Exophiala dermatidis, often associated with blastomycosis, was found in the mass before inoculation and during the initial stages of the fermentation. Examination of these indigenous fermented foods may provide clues as to how food production and preservation can be expanded and thereby contribute to improve nutrition in native tribes in the region.     

疏花水柏枝内生真菌QY-1的抗氧化活性分析

以从疏花水柏枝(Myricaria laxiflora)中分离的1株内生真菌QY-1为研究对象,为分析其体内及体外的抗氧化活性,对其发酵液及其提取物的活性进行了综合评价。对nr DNA内转录间隔区进行测序鉴定。分别采用总抗氧化力试剂盒、自由基清除试剂盒和还原力测定试剂盒评价发酵液及粗提物的体外抗氧化能力活性;对发酵液提取物及其主成分进行了大肠埃希菌、人神经母瘤细胞SH-SY5Y的体内抗氧化损伤保护作用分析。结果表明QY-1是1株球毛壳菌(Chaetomium globosum),其粗提物具有很高的抗氧化活性,总抗氧化活力、自由基清除率及总还原力均接近维生素C的50%,远高于国际报道水平。且其发酵液提取物有促进细胞增殖和抗氧化保护作用,显著提高大肠埃希菌细胞和神经细胞在H2O2胁迫下的存活率。其粗提物可保护神经细胞膜的完整性,有效减低乳酸脱氢酶(LDH)的渗漏率。从粗提物中分离到一种主成分SF2,可显著抑制凋亡蛋白Caspase 3和Caspase 9的活性。结果表明内生真菌球毛壳菌QY-1不管在体内还是体外都具备较强的抗氧化能力,是一种具有潜在开发价值的天然抗氧化剂资源。