Effect of some traditional processing operations on the functional properties of African breadfruit seed (Treculia africana) flour

The effect of germination, fermentation, roasting and defatting on the proximate composition, water absorption capacity (WAC), oil absorption capacity (OAC), foaming capacity (FC), foaming stability (FS), emulsion capacity (EC), emulsion stability (ES), packed bulk density (PBD), least gelation concentration (LGC) and protein solubility (PS) of breadfruit seed flour (BSF) was investigated. WAC, OAC, FC, EC, PBD and LGC obtained are 190-380%; 130.3-200.5%; 2.3-60.4%; 12.4-52.9%; 0.4-0.6 g/ml; 6-12% (w/v) and 200-420%; 176.4-320.6; 4.2-70.8%; 20.2-60.4%; 0.5-0.7 g/ml; 0.5-0.8% (w/v) in the full fat and defatted flours respectively. Foams were more stable in the untreated; least in fermented and roasted samples. Defatting improved the FC, FS and EC; roasting and fermentation reduced EC of full fat BSF; Processing and defatting had no effect on the PBD; roasting and germination increased LGC while defatting and fermentation reduced it. Full fat flours had the lowest PS at pH 4 and the highest at pH 8. Fermented full fat BS flour had the highest PS at pH 5 and 8. Defatted germinated, raw dried and roasted BSF had lowest PS at pH 4; PS of fermented BSF is lowest at pH 3 and highest at pH 2.     

Structural and chemical changes in cocoa (Theobroma cacao L) during fermentation,drying and roasting

Cocoa seeds and pulp were fermented for 144 h, followed by natural drying. The tegument was removed and the cotyledons were broken into nibs which were roasted at 150 °C for 30 min. Non‐fermented material, material fermented for 24, 48 and 72 h, material fermented for 144 h and then dried, and also the roasted nibs, were all prepared for chemical and microscopic analyses. Light microscopy revealed the presence of anionic and cationic residues and of neutral sugars. During fermentation there was a reduction in the cytoplasmic content of phenolic compounds and in the number of protein bodies. The cell wall showed a reduction in anionic residues and a loss of crystallinity. These alterations were maximum after 72 h. Drying and roasting increased the number of damaged cells and reduced the amount of cytoplasmic material. The chemical analyses generally confirmed the microscopy results. The concentration of amino‐terminal groups and total free amino acids increased during fermentation (up to 72 h), but returned to the initial values after roasting. The principal chemical changes were related to reducing sugars, free amino acids, proteins and phenols, and PCA was suggested as a useful tool to compare different samples. Microscopic analysis revealed the degradation of protein and phenolic bodies and cellular damage during roasting. © 2000 Society of Chemical Industry     

Influence of Heat Pretreatments of Oat Grain on the Viscosity of Flour Slurries

Heat treatment of oat grain had significant effects on the viscosity of flour slurries. Steamed oats produced highly viscous flour slurries, whose viscosity increased with time, whereas the viscosity of flour slurries produced from raw or roasted (104°C for 120 min) oats was much lower and degraded rapidly. Slurry viscosity was correlated with (1→3), (1→4)-β-D -glucan concentration in the flours and treatment of slurries with lichinase lowered viscosity significantly. Effects of steaming were partially reversed by roasting treatment and vice versa. Mixtures of equal amounts of raw and steamed flour resulted in slurries more viscous than either flour alone, but that viscosity degraded after 3 h to less than the mean viscosity of the steamed and raw controls. Water-soluble extracts from steamed flour had about twice the viscosity of raw or roasted flour extracts, but contained only 80% of the (1→3), (1→4)-β-D -glucan present in those extracts. Molecular weight analysis of soluble carbohydrates from raw, roasted and steamed soluble extracts indicated the molecular weight of β-glucans in these extracts was similar. However, if extracts were made from slurries that had incubated for 3 h, extensive degradation of β-glucans was evident in raw and roasted samples. It is likely that enzymic degradation of (1→3),(1→4)-β-D -glucans is responsible for much of the decreased raw and roasted flour slurry viscosity over extended time periods, but different heat treatments appear to also affect (1→3), (1→4)-β-D -glucan polymer interaction. © 1997 SCI.     

The pasting behaviour of lactic‐fermented and dried uji (an East African sour porridge)

The effects of sun‐, cabinet‐, and drum‐drying on the behaviour of submerged culture lactic‐fermented pure cassava, maize and finger millet and composites of maize–finger millet and cassava–finger millet were investigated in a Brabender amylograph. The cereal flours and maize–finger millet composite had higher onset and peak gelatinization temperatures but lower peak viscosities than cassava or cassava–finger millet composites. Fermentation alone or in combination with drying increased the viscosity of the flours, except for the fermented and drum‐dried cassava–finger millet composite flour. This increased viscosity of uji on fermentation and drying makes it more difficult to cook. Fermented and drum‐dried flours recorded high initial viscosities, at 30 °C, when the amylograph was switched on. Copyright © 2003 Society of Chemical Industry     

Fermentation of Vigna sinensis var. carilla flours by natural microflora and Lactobacillus species

Natural fermentation and an inoculum containing 10% (vol/vol) Lactobacillus fermentum or Lactobacillus plantarum were used to obtain fermented flours from Vigna sinensis L. var. carilla seeds that had been washed with distilled water and dried at 55 degrees C for 24 h. To optimize the fermentation parameters (lactic acid bacterium level, bean flour concentration, and fermentation time), several small-scale fermentation processes were carried out. On the basis of the results obtained, fermentor-scale bean fermentation by microorganisms present on the seeds (natural fermentation [NF]) or by inoculation with L. plantarum (PF) was carried out at 37 degrees C for 48 h with a concentration of 300 g of bean flour per liter. The fermented flours (NF and PF) were also autoclaved. The levels of alpha-galactosides, inositol phosphates, trypsin inhibitor activity (TIA), soluble carbohydrates, starch (total and available), total available carbohydrates, thiamin, and riboflavin were determined for the processed cowpea flours, and microbiological studies were also carried out. The beans' levels of alpha-galactosides, TIA, and inositol hexaphosphate decreased by 95, 50, and 85%, respectively, for the NF flour and by 87, 27, and 85%, respectively, for the PF flour, while inositol pentaphosphate and inositol tetraphosphate were present in both fermented flours. The sucrose content decreased, and glucose, fructose, and galactose appeared as a result of fermentation. The levels of total available sugars and thiamin decreased by 2 and 12% and by 69 and 43%, respectively, while the riboflavin content increased by 106 and 94% for NF and PF flours, respectively. When NF and PF cowpea flours were heated in an autoclave for 20 min, TIA decreased further (by 80 and 56%, respectively). According to the chemical and microbiological results obtained in this study, fermentation with L. plantarum and autoclaving is an excellent process by which to produce a new functional food from the seed of a cheap legume (Vigna sinensis L. var. carilla).     

Effect of amylase-rich flour (ARF) treatment on the viscosity of fermented complementary foods

Grains of cowpea and maize and slices of fresh cassava, cocoyam, plantain, and yam were steep-fermented in water, while flours from the same plant materials were fermented by backslopping for 24 to 30 hours. The pH and apparent viscosity of the gruels from the resulting flours were determined. Loss in weight due to fermentation was higher in fresh tubers than in dry grains. The pH of the flours decreased during fermentation. Measurements showed that the apparent viscosity only of gruels from flours produced by backslopping decreased after 24 hours. The apparent viscosity of gruels from steep-fermented flours was higher than that of the unfermented flours and those produced by backslopping. The apparent viscosity reduction of gruels from steep-fermented flours using amylase-rich flour (ARF) from five-day white sorghum malt was better with the prepared gruels than when applied to the flour-in-tap-water suspension before it was used to prepare gruels. Viscosity reduction using ARF was also better with the fermented gruels than with gruels from unfermented flours. The implications of these results for the formulation of complementary flour blends for infant feeding are discussed.     

发酵方式对玉米粉品质和风味特性的影响

以未经发酵的玉米粉为对照,对自然发酵、植物乳杆菌、酿酒酵母菌及复配菌种（植物乳杆菌和酿酒酵母菌）发酵制得的玉米粉品质进行分析。结果表明：相比未发酵玉米粉,发酵后玉米粉中粗蛋白、粗脂肪、粗纤维和粗灰分含量显著降低（P<0.05）,总淀粉含量显著上升（P<0.05）;发酵使玉米粉的糊化温度显著升高（P<0.05）,自然发酵和复配菌种发酵后的玉米粉衰减值和回生值显著降低（P<0.05）,玉米粉的稳定性和抗老化性能提高;植物乳杆菌和复配菌种发酵对玉米粉的微观结构影响较大;酿酒酵母菌和复配菌种发酵产生的香气和代谢产物有效改善了发酵玉米粉的不良气味。通过不同发酵方式的对比得知,植物乳杆菌、酿酒酵母菌和复配菌种发酵可以将玉米粉自然发酵所需的13 d分别缩短至72、18 h和48 h,有效提高了生产效率。经复配菌种发酵后制得品质、风味且加工性能更加优良的玉米粉。     

PROCESSING AND FUNCTIONAL PROPERTIES OF YAM BEANS (SPHENOSTYLIS STENOCARPA)

The proximate and selected functional properties of five flours from yam bean (YB) made after the grains were not processed (raw) and processed as boiled, fermented, roasted and malted, were determined. The functional properties were water and fat absorption, gelation, emulsification and whippability. An improvement was observed for protein content of flours processed beans compared to raw flour. Fermentation improved the oil content of the flour. The emulsifying and foaming capacities (50.7 and 40.20%, respectively) observed for raw flour were significantly higher than those for the flours from processed bean. Gelation was significantly (P < 0.05) increased and decreased by fermentation and malting of the bean, respectively. The water absorption capacities ranged from 131.9% in raw flour to 218.8% in flour boiled beans. There were no significant (P > 0.05) differences in the fat absorption capacities of all flours except for the one of fermented beans (0.40 mL/g), which was significantly lower than the value (0.73 mL/g) obtained for the flour from boiled beans. Although a high foaming capacity was observed for raw flour, it was less stable when compared with that of the processed bean flours. Overall, YB flour was found to exhibit good functional properties, and has a great potential for use as an ingredient in selected food systems.     

Evaluation of functional,antinutritional, pasting and microstructural properties of Millet flours

In the present study finger and pearl millet grains were milled and sieved to obtain flour. The flours were evaluated for chemical composition, nutritional, antinutritional, pasting and micro structural properties. Significant difference (p < 0.05) in nutrient and antinutrient contents was found among the millet flours. Protein, ash and fiber content of millet flours vary from 7.3 to 8.0 g/100 g, 2.73 to 5.16 g/100 g and 3.03 to 3.05 g/100 g. Results obtained for antinutrient factors in finger and pearl millet flours were (3.5 mg/g) and (2.2 mg/g) for tannic acid and (6.1 mg/g) and (9.2 mg/g) for phytic acid respectively. Mineral availability of pearl and finger millet flour (mg/100 g) was (109.2–139.2), (0.73–4.2), (1.18–8.7.0), (15.03–17.36) and (67.53–30.03) for calcium, zinc, iron, sodium and potassium respectively. Finger millet flour showed higher peak viscosity, breakdown, final and set back value compared to pearl millet flour. Findings from the scanning electron microscopy analysis showed microstructural differences in both millet flours. FTIR analysis showed that both finger and pearl millet flours possessed O–H and C–H compounds.     

一种波杂饮料的工艺研发

波杂是一种以谷物为原料经传统发酵而成的民族特色发酵饮品。以大米粉、小米粉、玉米粉为原料,以酵母菌、乳酸菌作为发酵剂进行发酵生产,考察不同发酵时间下波杂的pH值、总酸、总糖、灰分、蛋白质、固形物含量、酒精度和黏度变化,最终根据感官评价评选出最优发酵时间。试验结果表明,发酵时间为48 h时口感最好,特有的发酵酒风味更醇厚,在此条件下,波杂pH值为4.0,总酸含量为2.8 g/L,总糖含量为3.4 g/L,灰分含量为2.0 g/L,固形物含量为2.5%,酒精度为1%vol,黏度为39 cP。     

Chemical composition and functional properties of raw and roasted Nigerian benniseed (Sesamum indicum) and bambara groundnut (Vigna subterranean)

Benniseed and bambara groundnut seeds were roasted at 80 and 120 °C for 10–60 min. For both flours, the effects of roasting temperature and time on selected functional properties and chemical composition were determined, as were the effects of pH on the emulsification capacity and nitrogen solubility. The chemical constituents of the raw flours were present at higher concentrations than those of the roasted flours except for fat and ash. Protein concentrates of both flours contained 80.5–81.5% crude protein as the major constituent. Nitrogen solubility was lowest at pH 4.0 for raw and roasted benniseed flour and pH 5.0 for raw and roasted bambara groundnut flour. Roasting generally lowered the nitrogen solubility and increased the water and oil absorption capacities while decreasing the foaming capacity and emulsification capacity of both flours.     

干热处理对藜麦淀粉结构和理化性质的影响

以高筋小麦粉为原料添加酵母制作面团,在温度28℃、湿度80%条件下发酵1～6 h,提取小麦淀粉。研究发酵时间对小麦直链淀粉含量、损伤淀粉含量、粒径、颗粒表面结构、糊化及消化特性的影响。结果表明：面团发酵1 h后直链淀粉含量和损伤淀粉含量均显著低于原淀粉(P<0.05)。快速黏度分析结果表明,发酵1 h的小麦淀粉峰值黏度、热浆黏度和冷浆黏度最低。发酵处理后淀粉的粒径均小于原淀粉,其中发酵5 h的平均粒径最小。扫描电镜结果表明,发酵6 h的小麦淀粉颗粒表面出现破裂现象。体外消化实验表明,发酵5 h和6 h小麦淀粉的消化速率最高,发酵后抗性淀粉含量低于原淀粉,而慢消化淀粉含量高于原淀粉(P<0.05)。     

Effects of different types of soy sauce on the formation of heterocyclic amines in roasted chicken

The objective of the study was to determine the effect of different types of soy sauce and marinating time on the formation of heterocyclic amines (HCAs) in roasted chicken. Chicken breast samples were marinated with sweet, salty, light and dark soy sauce at 0, 3, 6 and 12 h (control treatment was the chicken without marinade). The concentrations of free amino acids, sugars and creatinine were determined before roasting while HCA concentrations were determined after roasting. All types of soy sauce significantly increased (p ≤ 0.05) the concentration of HCAs in roasted chicken with increasing marinating time. The highest increment of total concentration of HCAs was found in samples marinated with light soy sauce (887%) followed by dark (375%), salty (193%) and sweet (169%) at 12 h. PhIP (2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine) showed a substantial reduction in samples only momentarily marinated with sweet, salty and dark soy sauce (0 h). Free amino acids were found to be more strongly correlated with the formation of HCAs than reducing sugars or creatinine.     

Effect of drying lactic fermented uji (an East African sour porridge) on some carboxylic acids

Maize, finger millet, cassava, maize–finger millet and cassava–finger millet flours were fermented and sun‐, cabinet‐, or drum‐dried. Total titratable acidity (TTA), fixed acidity (FA), pH and carboxylic acids were determined. The TTA of the non‐fermented flours ranged from 0.22%(w/w) lactic acid in cassava to 0.36%(w/w) lactic acid in the maize–finger millet composite. After fermentation the TTA ranged from 3.26%(w/w) lactic acid in cassava–finger millet to 4.54% in maize‐finger millet while FA ranged from 2.86% in cassava–finger millet to 4.26% in cassava and maize–finger millet. Fermentation decreased the pH from about 5.5 to 3.7–4.1. Drying did not change the pH but TTA decreased by 20–60%. Acetic acid levels in the fermented slurries varied from 0.80 to 0.95 µg per 5 µg while those of hexanoic acid varied from 0.9 to 1.8 µg per 5 µg. Propionic acid was absent in the fermented slurries. Acetic and formic acids were completely lost when the fermented slurries were dried. On average hexanoic acid losses on drying varied from 33% in maize to 91% in cassava fermented slurries. These losses were not significantly influenced by the drying system. In sensory evaluation panellists could not detect flavour loss as a result of drying. © 2000 Society of Chemical Industry     

Pasting,thermal, gel texture,resistant starch and colour properties of unripe banana flour from 10 desert banana varieties cultivated in South Africa

Unripe banana flour is a potential commercial ingredient in various food products for increased resistant starch and reduced gluten contents. In the present study, the pasting (rapid visco-analysis), gel texture (penetration test), thermal (differential scanning calorimetry), colour (tri-stimulus colour indices) and the resistant starch properties of unripe banana flour produced from different dessert banana varieties (n?=?10) cultivated in South Africa, were analysed and juxtaposed to wheat and maize flour. The functional properties varied significantly (p?≤?0.05) between banana varieties, and from wheat and maize flours, to various extents. Selected functional property ranges of unripe banana, wheat and maize flours, respectively included; flour colour index (63.16–76.42, 77.34 and 80.96), paste viscosity (405.5–556.6, 124.7 and 115.6 RVU), gelatinization temperature (64.67–71.21, 71.11 and 69.95?°C), gel firmness (7.24–11.44?×?10^??2 N, 3.49?×?10^??2 N and 6.56?×?10^??2 N) and resistant starch content (19.9–47.4, 2.8 and 2.2% w/w). Multivariate analysis (principle component analysis) showed that the unripe banana flours from different varieties were distinguished from each other based on the pasting temperature. The unripe banana flours were distinguished from both wheat and maize flour based on breakdown and peak paste viscosities. The breakdown viscosity was the most positively related measure to the resistant starch content with a linear regression R-squared value of 0.898, indicating a significant role played by granule structure in resistance to enzymatic hydrolysis. The present research demonstrates that selection of appropriate dessert banana variety is important when replacing staple flours (wheat and maize) with unripe dessert banana flour as a functional ingredient.     

Natural fermentation of lentils Influence of time, temperature and flour concentration on the kinetics of thiamin, riboflavin and niacin

Lentils (Lens culinaris, var. vulgaris cultivar Magda-20) were naturally fermented for 96 h at different lentil flour concentrations (79, 150 and 221 g/l) and temperatures (28, 35 and 42°C). During fermentation, samples were taken at 24-h intervals and the changes in thiamin (vitamin B₁), riboflavin (vitamin B₂) and total and available niacin (vitamin B₃) were investigated. Preparation of the lentil flour suspension to be fermented (i.e. the process of mixing the flour and sterilized tap water) caused an increase of the available niacin content in all batches, while changes in thiamin and riboflavin content were related to the conditions in which the preparation of the suspensions was carried out. The whole natural fermentation process (from the raw state to after 96 h of fermentation), either did not affect or produced a slight decrease in the thiamin content of lentils. In contrast, riboflavin, available niacin and total niacin contents increased throughout the 96 h period, which ended with a 35?–?82% increase of riboflavin, a 24?–?91% increase of available niacin and a 20?–?58% increase of total niacin. The temperature during the fermentation procedure had significant effect on the levels of thiamin and riboflavin in fermented lentils. To obtain lentil flours with an improved amount of riboflavin and available niacin with a minimum loss of thiamin, the natural fermentation of lentils should be carried out for 96 h at 42°C and with a lentil flour concentration of 221 g/l.     

Natural fermentation of lentils. Functional properties and potential in breadmaking of fermented lentil flour

The effects of fermentation on functional properties of lentil flour and rheological properties of doughs and breads produced from blends of wheat and fermented lentil flour were studied. Lentil protein solubility was higher at neutral pH than acid pH; the lowest and highest protein solubility values were observed at pH 4.0 and pH 7.0, respectively. Water hydration capacity and fat binding capacity of fermented lentil flour (FLF) were always higher than those of non-fermented lentil flour (NFLF), irrespective of fermentation temperature (28–42°C) and flour concentration (79–221 g/l). Emulsifying properties of NFLF were similar to the properties of other legume flours in the range used in experiment. In contrast, the emulsion capacity and stability of FLF were very low and flours fermented at 42°C did not even form emulsion. Rheological properties of doughs made from wheat-fermented lentil blends were similar to those from wheat flour with the addition of other legume flours such as pea and bean. Good quality breads were produced at 2.5 to 10% NFLF and FLF supplementation (except for bread with 10% FLF addition which was middle quality).     

Effect of heat-moisture treatment for utilization of germinated brown rice in wheat noodle

Effect of heat-moisture treatment of germinated brown rice (GBR) on the texture and cooking quality of the noodles containing mixtures of wheat and GBR flours was investigated. With the increase in GBR content, hardness and tensile strength of the composite noodles decreased and cooking loss and water absorption increased. Pasting viscosity of the flour mixtures was significantly decreased by increasing the amount of GBR. Heat-moisture treatment of GBR (17 or 20 g/100 g moisture at 100 °C for 4 h), however, apparently increased the pasting viscosity and improved the texture and cooking quality of the composite noodles. The mixture of wheat and a treated GBR (1:1 weight ratio) showed a pasting viscosity similar to pure wheat flour. The noodle containing the heat-moisture treated GBR flours showed the lower cooking loss, and higher hardness and tensile strength than the noodle containing untreated counterparts. Among the treated GBR flours tested, the GBR treated at 100 °C for 4 h at a moisture level of 17 g/100 g was the most acceptable in terms of cooking quality and textural property, close to those of the noodle of pure wheat flour. Substitution with the heat-moisture treated GBR, however, made the noodle darker because of thermal discoloration of GBR.     

Effect of superheated-steam roasting on physicochemical properties of peanut (<Emphasis Type="Italic">Arachis hypogea</Emphasis>) oil

Peanut (Arachis hypogaea) is an important source of protein and lipid globally. The effect of superheated-steam roasting on quality of peanut oil was evaluated based on physicochemical quality parameters. Three roasting temperatures (150, 200, and 250 °C) were used for different periods of roasting time and the obtained results were compared with those of conventional roasting. At 250 °C, superheated-steam roasted peanuts yielded more oil (26.84%) than conventionally roasted peanuts (24.85%). Compared with conventional roasting, superheated-steam roasting resulted in lower oil color, peroxide, p-anisidine, free fatty acid, conjugated diene and triene, and acid values and higher viscosity and iodine values in the roasted peanut oil. These values were significantly different from each other (p < 0.05). The fatty acids in roasted peanut oils were affected by roasting temperature and time for both the roasting modes. The superheated steam technique can be used to roast peanuts while maintaining their favorable characteristics.     

The effects of natural fermentation on the physical properties of rice flour and the rheological characteristics of rice noodles

The effects of fermentation of whole polished rice grains on the physical properties of rice flour and the rheological characteristics of rice noodles were investigated. Natural fermentation had little effect on the crystalline structure of rice starch, as measured by X‐ray diffraction, but the ratio of the crystalline to the amorphous regions increased. The thermal properties of rice flours were determined using differential scanning calorimetry and a rapid viscosity analyser (RVA). The gelatinization temperature, T_p, and the RVA peak viscosity of rice flour decreased, while the gelatinization enthalpy, ΔH, increased after fermentation. The FTIR spectra of fermented and control rice flours were similar. Fermented rice starch granules had slight superficial corrosion when examined using scanning electron microscopy. Fermentation may thus change the amorphous region of the starch granule as well as the chemical components and thereby modify both physical properties of rice flour and rheological characteristics of rice noodles.