Microbial communities and malt quality of durum wheat used in brewing

Durum wheat (Triticum durum Desf.) has potential as an adjunct in brewing given its agronomic, chemical and technological properties. The aim of this work were to identify the cultivable microflora and evaluate the technological quality of the durum wheat variety ‘Senatore Cappelli’ grown and used by a craft brewery in Sardinia, Italy. The isolated bacterial strains were mainly rhizospheric (Kocuria rizophila, Microbacterium aerolatum and Bacillus pumilus) and associated with the microbiota of wheat (Staphylococcus spp.). None have been reported previously as spoilage species in brewing. The dominant yeast genera were Cryptococcus spp. and Rhodotorula spp., followed by Saccharomyces cerevisiae. The dominant filamentous fungus genera were Alternaria and Rhizopus. Low levels of mycotoxigenic Fusarium spp., Aspergillus spp. and Penicillium spp. were isolated. However, the levels of deoxynivalenol, T2‐HT2, fumonisin, aflatoxin and ochratoxin detected in the malt and grain were below the thresholds defined by European law. Malt obtained from raw grain showed interesting technological properties, but required specific malting parameters different from those of common wheat and barley. These data suggest that the use of locally grown durum wheat in brewing can increase sustainability and reduce costs, while reinforcing the link with the terroir and promoting reduced mycotoxin levels. © 2019 The Institute of Brewing & Distilling     

In vitro digestibility of Bacillus fermented soya bean

Bacillus fermented legume products include among others dawadawa and soumbala made from African locust bean, and natto and kinema made from soya bean. Bacillus subtilis is the dominant species involved in the fermentation. During Bacillus fermentation for 48 h of autoclaved soya bean the quantity of soluble and dialyzable matter increased from 22% and 6% up to 65% and 40%, respectively. Protein and carbohydrate degradation during fermentation of soya bean with several Bacillus spp. was investigated and appeared to be substantial during the first 18 h of fermentation resulting in the release of high levels of peptides and oligosaccharides. In vitro digestibility was increased from 29% up to 33–43% after Bacillus fermentation for 48 h. It was shown that Bacillus spp. were able to degrade soya bean macromolecules to a large extent resulting in water-soluble low molecular weight compounds. In vitro digestion of Bacillus fermented soya bean using gastrointestinal enzymes only slightly increased the amount of dialyzable matter, which clearly demonstrated the beneficial effect of Bacillus fermentation on food nutrient availability.     

In vitro digestibility of processed and fermented soya bean,cowpea and maize

Tropical legumes, ie soya bean and cowpea, were pre‐treated and subsequently fermented using pure cultures of Rhizopus spp. Impact of soaking, cooking and fermentation of the legumes on their digestibility was determined using an in vitro digestion method. Processing of white maize included, amongst others, natural lactic acid fermentation, cooking and saccharification using barley malt. An in vitro method was standardised to carry out comparative determinations of the dry matter digestibility of cereal and legume food samples as a function of processing conditions, without attempting to exactly mimic gastrointestinal digestion. Using this method based on upper digestive tract digestion, it was observed that digestibility of the legumes increased during cooking and fermentation. Cooking improved the total digestibility of both soya bean and cowpea from 36.5 to 44.8% and from 15.4 to 40.9% respectively. Subsequent fungal fermentation increased total digestibility only by about 3% for both soya bean and cowpea. Digestibility was also influenced by fungal strain and fermentation time. Cooking and subsequent saccharification using malt almost tripled total digestibility of white maize from 25.5 to 63.6%, whereas lactic fermentation of maize had no effect on in vitro dry matter digestibility. Although total digestibility of cooked legumes was only slightly improved by mould fermentation (3% for both soya bean and cowpea), the level of water‐soluble dry matter of food samples increased during fermentation with Rhizopus oryzae from 7.0 up to 27.3% for soya bean and from 4.3 up to 24.1% for cowpea. These fermented products could therefore play a role as sources of easily available nutrients for individuals suffering from digestive disorders. © 2000 Society of Chemical Industry     

Estimating Barley Character for Shochu Using a Single Kernel Characterization System (SKCS)

The SKCS (Single Kernel Characterization System) is a device for measuring the physical properties of whole grain. Using the SKCS, the physical properties of barley produced in Australia in 2001 were examined in relation to their suitability for shochu production (shochu is a Japanese clear distilled beverage with an alcohol content of ?25%). The hardness of whole grain showed a positive correlation with pearling, but negative correlations with both broken kernel ratio and conversion power. Softer endosperms facilitated crushing and fermentation (i.e. fermentation potential). From these correlations, quality characteristics of barley for shochu could be deduced. The measurement of barley hardness with the SKCS is important in the evaluation of barley for shochu production and the hardness of the whole grain could be used as one indicator in the evaluation of barley. The procedure can be carried out locally and rapidly.     

Influence of Fermentation Time and an ‘Indigenous Tenderiser’ (Kanwa) on the Microbial Profile,Chemical Attributes and Shelf-Life of Rice Masa (a Nigerian Fermented Product)

Investigations on the influence of fermentation time, ‘Kanwa’ (an indigenous tenderiser and a flavouring agent) and potassium sorbate (0·5, 1·0 or 1·5 g kg⁻¹) were conducted by examining the microbial profile, chemical attributes and shelf-life of rice ‘Masa’ (a Nigerian fermented product). Various types of microorganisms occurred at the initial stages of rice slurry fermentation and these included fungi (Aspergillus spp, Penicillium spp, Saccharomyces spp, Rhizopus spp) and bacteria (Lactic acid bacteria, Bacillus spp, Enterobacter spp and Acetobacter spp). But beyond 8 h fermentation time, fewer types of micro-organisms (Lactobacillus spp, Saccharomyces spp and Rhizopus spp) were isolated.Total aerobic counts increased significantly (P=0·05) as fermentation progressed (0, 6 or 12 h), with lactic acid bacteria (LAB) and yeasts dominating and probably contributed to the sour–sweet spongy characteristic of the rice Masa. But after fermentation and baking process, the rice Masa became dominatedand spoilt by Bacillus spp, Lactobacillus spp and Saccharomyces spp withstorage time. Longer fermentation time resulted in a less acceptable product,being more acidic. Rice Masa produced from a 6 h fermentation showedbetter sensory qualities (aroma and visual appearance). Use of Kanwa(Na₂CO₃.NaHCO₃.2H₂O) improved aroma but was detrimental to visualappearance and spoilage was accelerated, probably due to higher pH. Potassium sorbate at higher concentrations (1·0 and 1·5 g kg⁻¹) induced beneficial antimicrobial effects and reduced the microbial load thereby prolonging the shelf life of the rice Masa (treated with 1·5 g kg⁻¹) by about 3 days.     

Properties of soya milk and tofu prepared with γ-irradiated soya beans

Soya beans (Glycine max) ‘hwang keum’ were γ-irradiated at dose levels of 0, 2.5, 5, 10 and 20 kGy and the effects of the irradiated soya beans on soya milk and tofu properties were studied. An irradiation dose of 5 kGy caused an increase in yield of soya milk and tofu while having very little effect on their quality. The properties of tofu prepared with the soya beans irradiated at 2.5–5 kGy showed no significant difference from the non-irradiated control. However, at higher doses (10–20 kGy), decreases in yield, water holding capacity and sag value of tofu were observed. Compared with the non-irradiated control, hardness and fracturability in the texture of tofu were both significantly increased when the soya bean had been irradiated at 10–20 kGy, while cohesiveness and adhesiveness decreased. The changes in color values of soya milk and tofu were pronounced at 20 kGy.     

Comparison of Industrial Scale Ethanol Production from a Palmyrah‐Based Carbon Source by Commercial Yeast and a Mixed Culture from Palmyrah Toddy

Palmyrah (Borassus flabellifer) based products were used as an alternative carbon source for industrial scale ethanol production. The fermentation medium was enriched with spent wash obtained from a distillation column. The performance of a commercially available baker's yeast in the media was compared with a ‘palmyrah toddy mixed culture’ where the organisms were obtained from the sedimentation of palmyrah toddy. In a laboratory scale study, the ethanol produced from a palmyrah fruit pulp extract, diluted with distilled water, was 16.5 gL^?1 (36 h) and 13.0 gL^?1 (48 h) with ‘palmyrah toddy mixed culture’ and baker's yeast respectively. The ‘palmyrah toddy mixed culture’ performed better than the baker's yeast with palmyrah fruit pulp extract, diluted either with distilled water or spent wash. Among the different palmyrah based carbon sources, both cultures preferred molasses diluted with spent wash and both performed best in the medium containing the spent wash supplemented with sucrose. In a 5,000 L industrial scale fermentation of 20° Brix molasses supplemented with 10 gL^?1 ammonium sulphate, 72 gL^?1 and 65 gL^?1 ethanol was produced by the ‘palmyrah toddy mixed culture’ (72 h) and the baker's yeast (90 h) respectively. As the performance of the ‘palmyrah toddy mixed culture’ was better than that of the baker's yeast, the former was selected for the industrial scale studies of molasses fermentation media diluted with spent wash. In these studies the temperature reached 42°C by 36 h and resultant cell death was observed. However ethanol production was higher and more rapid in the molasses diluted with spent wash, rather than in the molasses diluted with tap water and supplemented with (NH₄)₂SO₄. Cell recycle operation obviated the interruption in fermentation caused by temperature induced cell death and increased rates and efficiency of ethanol production were observed.     

Contamination with storage fungi of human food from Cameroon

In a mycological study, a total of 95 human food samples were investigated to evaluate the incidence of fungal contamination in Cameroon by conventional identification method and partly confirmed by DNA sequencing. The isolated fungal spp. were further studied to determine their toxigenic potentials. The investigation revealed the predominance of Aspergillus and Penicillium with 96% of samples contaminated with at least one species of these fungi, whereas the incidence of co-contamination of samples was 85%. Aspergillus flavus and Aspergillus parasiticus (Flavi section) were the most predominant species contaminating mainly maize and peanuts. In addition, P. crustosum and P. polonicum were the most common contaminants belonging to the genus Penicillium. On the other hand, A. ochraceus (Circumdati section) registered a low incidence rate of 5%, including other members of the Aspergillus group. Other members of the genera Rhizopus and Alternaria spp. were also registered in the study. A majority of fungal strains of A. ochraceus, A. parasiticus, P. crustosum and P. polonicum isolated were toxigenic, producing the mycotoxins tested for, while none was detected in cultures of A. fumigatus. The high incidence rate of fungi contamination coupled with their potentials in producing mycotoxins gives a strong indication that the samples tested may likely be contaminated with various mycotoxins. There is need for further study to assess the incidence of mycotoxins contamination in similar food samples.     

Dephosphorylation of phytate compounds by means of acid phosphatase from Aspergillus niger

A non-purified preparation of intracellular acid phosphatase (EC 3.1.3.2) from a waste mycelium of Aspergillus niger was utilised for dephosphorylation of phytate compounds present in food and feed ingredients. The enzymic hydrolysis of p-nitrophenylphosphate was used for assaying acid phosphatase activity, expressed in standard units (u). The hydrolysis of phytate phosphorus in wheat bran, soya bean meal and fully formulated feedstuffs for broilers (Galus galus; ‘Cornish’ × White Rock') was carried out at 40°C, a pH value of 4.5 and an enzyme dosage ranging from 12 to 30 u g^?1. Complete dephosphorylation of soya bean protein isolates was performed at 60°C, a pH value of 4.5 and an enzyme dosage of 12 u g^?1. In the gastrointestinal tract of broilers the in-vivo dephosphorylation of phytates present in feed was observed when the preparation of acid phosphatase was added to the diet.     

Rich nutrition from the poorest – Cereal fermentations in Africa and Asia

Cereal fermentations in Africa and Asia involve mainly the processing of maize, rice, sorghum and the millets. Lactic acid bacteria (Lactobacillus, Pediococcus), Enterobacter spp., yeasts (Candida, Debaryomyces, Endomycopsis, Hansenula, Pichia, Saccharomyces and Trichosporon spp.) and filamentous fungi (Amylomyces, Aspergillus, Mucor, and Rhizopus spp.) contribute to desirable modifications of taste, flavour, acidity, digestibility, and texture in non-alcoholic beverages (e.g., uji, and ben-saalga), porridges (e.g., mawè) and cooked gels (e.g., kenkey, idli, and mifen). In addition, alcoholic beverages (beers such as tchoukoutou and jnard; and spirits e.g. jiu) are obtained using malt, or using amylolytic mixed microbial starter cultures as generators of fermentable substrates. Wet processing, marketing of multi-purpose intermediate products, co-fermentation for texture and nutrition, and mixed culture fermentations as practiced in indigenous fermentation processes are of interest for industrial innovation and for better control of natural mixed culture fermentation systems. On the other hand, the nutritional properties of traditional cereal fermented products can be enhanced by increasing their nutrient and energy density, as well as by increasing their mineral status by combining mineral fortification and dephytinization.     

Changes in phenolic compounds and Rancimat stability of olive oils from varieties of olives at different stages of ripeness

BACKGROUND: Recently, diets rich in natural foods and food‐derived components, such as phenolic compounds, have received a great deal of attention because they are perceived as ‘safe’ and ‘non‐medicinal’. In fact, some are known to function as chemopreventive agents against oxidative damage, cerebrovascular disease, and aging. RESULTS: Phenolic compounds, natural antioxidants present in virgin olive oil, play an important role in oil quality by contributing significantly to protecting oil stability against oxidation. In addition, polyphenols are the main contributors to olive oil bitterness, astringency and pungency. The data were fit by linear regression, giving Rancimat stability (h) = 0.18× Total polyphenols (mg L^?1) in the virgin olive oil. CONCLUSIONS: The practice of harvesting ripe olives as soon as possible to produce oils of high phenolic contents and thus high oxidative stability implies bitter and piquant oils, this being admissible for oils of some varieties but detrimental to others appreciated in the market for being more fruity and sweeter. Copyright © 2010 Society of Chemical Industry     

Vitamin E and Oxidative Stability of Soya Bean Oil Prepared with Beans at Various Moisture Contents Roasted in a Microwave Oven

Whole soya beans ( Glycine max ) at various moistures (96, 382 and 519 g kg⁻¹) were roasted by exposure to microwaves at a frequency of 2450 MHz and the effects on the tocopherols of soya beans were studied in rela-tion to chemical changes in the oils. The amounts of α-, β-, γ- and δ-tocopherols in the soya beans before microwave treatments ranged from 62 to 187, 43 to 89, 673 to 757 and 542 to 593 mg kg⁻¹ oil, respectively. Increasing moisture contents by soaking prevented, not only the reduction of tocopherols but also, the oxidative deterioration of soya bean oils during microwave roasting. The amounts of tocopherols still remained >80% of the original level in soaked soya bean oils after 20 min of roasting, and microwave roasting after soaking caused no significant differences ( P> 0·05, with few exceptions) in the chemical changes of the oils in comparison with those before soaking. These results implied that microwave roasting after soaking would be effective in making full-fat soya flour with high vitamin E without a burnt odour and browning from raw beans.     

Saponin content of soya and some commercial soya products by means of high-performance liquid chromatography of the sapogenins

Quantitative high-performance liquid chromatography of the sapogenins was used to estimate the saponin content of soya beans (Glycine max (L.) Merr.) and commercially prepared soya flours, protein concentrate, protein isolate and soya milks. The level of saponin in whole soya beans as estimated (0.47%) was in agreement with other recent estimates. Saponins were also found in the various soya flours (0.43–0.67%), protein isolate (0.76%), soya milks (0.022–0.026%) but not in the protein concentrate.     

Lactic acid fermentation of<Emphasis Type="Italic"> Brassica rapa</Emphasis>: chemical and microbial evaluation of a typical Italian product (<Emphasis Type="Italic">brovada</Emphasis>)

Brovada is an ancient traditional product from the northeast Italian region, included in any list of typical Italian products, which is obtained by natural fermentation of turnips (Brassica rapa). Turnips are cleaned and put in vats, alternating them with a layer of grape skins. Before covering the vat a mix of water and salt or water only is added. The vegetable fermentation is a spontaneous process caused by the microorganisms present on the various components (turnip and grape skins). A total 225 lactic acid bacteria (LAB) and 63 yeasts were isolated during this natural fermentation process. The main heterofermentative population was identified as Lactobacillus spp. while the major homofermentative LAB were Pediococcus spp., Candida spp. was the main yeast present. During the first 24 h of fermentation, the pH decreased rapidly to 3.7. At different steps of fermentation the headspace aroma compounds of brovada were analyzed by solid-phase-micro-extraction/gas chromatography/flame ionization detection to define the characteristic aroma profile of this particular product.     

响应面法优化贝莱斯芽孢杆菌发酵水豆豉的工艺条件

发酵产品的质量与微生物的产酶能力和发酵条件息息相关。为提高水豆豉的发酵品质,采用单因素法结合响应面法对一株高产豆豉纤溶酶的贝莱斯芽孢杆菌发酵水豆豉的条件进行优化,以获取最佳的发酵条件。首先利用单因素法缩小发酵时间、温度和接种量的范围,然后通过响应面法以水豆豉中的氨基酸态氮含量和豆豉纤溶酶活性为指标,确定最优发酵条件为:时间5d,温度35℃,接种量0.01%。最终发酵的水豆豉氨基酸态氮含量为8.95g/kg,豆豉纤溶酶活性为420.05IU/g,与市售相比,豆豉纤溶酶活性升高约400倍。该研究为贝莱斯芽孢杆菌发酵水豆豉提供了理论依据。     

Consistency,Polysaccharidase Activities and Non-Starch Polysaccharides Content of Soya Beans During Tempe Fermentation

The relation between consistency of soya beans, polysaccharidase activities and the non-starch polysaccharides (NSP) content of soya beans was investigated during tempe fermentation. The fermentations were carried out in a rotating drum reactor (RDR) as well as in the traditional stationary tempe process. The firmness of the soya beans decreased rapidly during the first day of incubation. At increased incubation temperatures the hardness of the beans decreased more rapidly. In the RDR glycosidase activities became significantly higher beyond 48 h of incubation compared with the traditional process. This might have resulted from (a) the better control of temperature and gas composition in the RDR, and/or (b) the agitation in the RDR. The content of arabinose, galactose and uronic acids in the water-unextractable solids of NSP decreased more rapidly than that of glucose, mannose, xylose and fucose. These results indicate that during enzymatic maceration of soya beans in tempe fermentation, the arabinogalactan and pectin fractions are preferentially solubilised. © 1997 SCI.     

Fatty Acid Composition of ‘Cerrado’ Seed Oils

The seeds of 28 species from ‘cerrado’, a typical savanna ecosystem of Brazil, were analysed for total lipid contents and fatty acid distribution. The seeds of 10 species presented contents above 150 g kg⁻¹, the highest yield reaching 335 g kg⁻¹. Distribution of fatty acids based on polyunsaturated compounds seems to be rare in seed oils from ‘cerrado’: only three seed oils were found to be based on linoleic acid and none on linolenic acid. Eight seed oils, four of them Fabales, presented palmitic acid as a dominant constituent. Half of the species presented oleic acid based seed oils. Two species stand out for unusual fatty acid distribution: Qualea grandiflora (Vochysiaceae) with 171 g kg⁻¹ of seed oil presenting 723 g kg⁻¹ of lauric acid and Serjania erecta (Sapindaceae) with 256 g kg⁻¹ of seed oil presenting 623 g kg⁻¹ of eicosenoic acid.     

The effect of sowing date and growth stage on the essential oil composition of three types of parsley (Petroselinum crispum)

Essential oils obtained by simultaneous distillation–extraction (SDE) from leaves, petioles and roots of three types of parsley (turnip‐rooted, plain leaf and curly leaf type), sown on three different dates, were analysed by GC‐MS (gas chromatography–mass spectrometry) analysis. Parsley plants were found to produce mainly β‐phellandrene, 1,3,8‐p‐menthatriene, α‐,p‐dimethylstyrene, myristicin, β‐myrcene and apiole. In some cases α‐ and β‐pinene were also found, whereas β‐elemene was detected, especially in the curly leaf type. The growth stage, plant tissue and date of sowing, as well as the climate conditions, all had a significant effect on the essential oil composition by altering the ratio of the above substances. Copyright © 2004 Society of Chemical Industry     

Saponin content of food plants and some prepared foods

Quantitative thin layer chromatography was used to estimate the saponin content of 20 common food plants and also of foods prepared from some of them. The food plants found to be richest in saponins were chickpeas (Cicer arietinum), soya beans (Glycine max), lucerne (alfalfa) sprouts (Medicago sativa) and varieties of Phaseolus vulgaris (navy beans, haricot beans, kidney beans). Saponins were not destroyed by processing or cooking. They were present in falafels (prepared from chickpeas), canned baked beans, canned broad beans and protein isolate from faba beans. However, the saponin content of a fermented soya bean product (tempe) was only half that of whole soya beans. Guar meal (Cyamopsis tetragonolobus) contains saponins but only a trace could be detected in samples of guar gum.     

Changes in nitrogen content and amino acid composition of navel oranges during ripening

Nitrogen content and composition of amino acids in juice and rind of navel oranges were studied. The compared varieties were ‘Navelina’ ‘Washington Navel’ and ‘Navelate’, early, mid-season and late types, respectively. Total N content in juice increased during the season with values from about 60 to near 100 mg 100 ml^?1 in Navelina and ‘Washington Navel’ and from 60 to about 80 mg 100 ml^?l in ‘Navelate’; amino N increased from 30 to 60 mg 100 ml^?lapproximately in the three varieties. The total N content in rind was quite similar in all cases, with values that decreased with time from 1 to around 0·6 g 100 g^?l dry weight (DW), 50–60% corresponding to the protein N. The main free amino acids in juice and rind at different maturity stages are tabulated. Proline represents at maturity around 50% of the total free amino acids in rind, with values near to 1·5 mmol 100 ml^?l in juice and over 5·0 mmol 100 g^?1 DW in rind. Total protein amino acids in rind decreased during maturation, reaching final values of about 20 mmol 100 g^?1 DW. Differences in composition among the three studied varieties are discussed.