Effect of solid state fermentation by Enterococcus faecalis M2 on antioxidant and nutritional properties of wheat bran

Wheat bran is the main by-product during wheat flour processing. Although wheat bran is rich in the bioactive compounds and antioxidant capacity, it is not widely utilized in its natural state. To improve the antioxidant and nutritional properties of wheat bran, a dominant strain, Enterococcus faecalis M2, was screened from lactic acid bacteria (LAB) isolated from various foods. Following solid state fermentation, the soluble dietary fiber content of wheat bran nearly quadrupled compared to the raw material. Total proportion of phenols, flavonoids, alkylresorcinols, along with the antioxidant capacity and free radical scavenging rate were significantly improved, particularly the ferulic acid content increased by 5.5 times. Additionally, the free amino acid content increased with degradation of wheat bran protein, whereas the level of anti-nutrient phytic acid decreased. The results of this study could provide an effective method for biological modification of wheat bran, which further enhance the health benefit and utilization of bran.     

Comparison of different rice flour- and wheat flour-based butter cookies for acrylamide formation

Acrylamide (AcA) contents of different rice flour- and wheat flour-based butter cookies baked at 130 °C for 20, 55, or 90 min were investigated. AcA contents of different flour-based cookies increased with baking time. Color parameters in terms of CIE L*, b*, C*, and ΔE values showed significant opposite correlation to the AcA formation in each of the raw flour cookie. The cookies based on white rice flour had the lowest AcA contents ranging from not detectable (ND) to 204 μg/kg, followed by cookies based on brown rice flour (ND to 450 μg/kg), white wheat flour (155 μg/kg to 661 μg/kg), and whole wheat flour (306 μg/kg to 982 μg/kg). Considerably lower AcA levels were found in the rice flour-based cookies than in the wheat flour-based cookies, as well as in the milled flour-based cookies than in the whole-grain cookies. Although the flour source was considered to play a primary role in determining the AcA content, AcA content was apparently not dependent on the quantities of reducing sugars and free asparagine in the starting raw flour and cookies during baking. In summary, given its reducing potential for AcA formation, rice flour could be used in the production of cookies safe from heat-induced contaminants.     

Mineral binding capacity of dephytinized insoluble fiber from extruded wheat,oat and rice brans

Insoluble fiber fractions from raw and extruded oat, rice and wheat brans were isolated and phytate removed. In vitro mineral binding studies were performed utilizing copper (Cu²⁺), calcium (Ca²⁺) and zinc (Zn²⁺) ions, which were added individually to enzymatically treated (Prosky et al., 1985), acid washed insoluble fiber residues from oat, rice and wheat brans. The enzymatic digestion step with alpha-amylase, protease and amyloglucosidase served to remove protein and starch from the samples. Mineral binding studies were performed on the insoluble fiber residue. Mineral content was determined by flame atomic absorption spectroscopy. Raw brans served as controls. A twin-screw extruder Model DNDG-62/20D, manufactured by Bühlerag (CH-9240, Uzwil, Switzerland) was utilized. The objectives of the study were to determine the total Cu²⁺, Ca²⁺ and Zn²⁺binding capacity of the dephytinized insoluble fiber from each bran; and to determine if extrusion screw speed affected the brans' insoluble fiber mineral binding capacity. Although dephytinized, the brans' insoluble fiber fraction bound Cu²⁺, Ca²⁺ and Zn²⁺ions. Oat bran bound more Cu²⁺, Ca²⁺ and Zn²⁺ than wheat bran, which bound more than rice bran. Extrusion processing did not affect the brans' insoluble fiber binding capacity to bind Cu²⁺. However, it increased the binding capacity of Ca²⁺ and Zn²⁺ of the insoluble fiber fraction from rice and oat brans.     

Rabadi fermentation of wheat: Changes in phytic acid content andin vitro digestibility

Fermentation of raw as well as autoclaved wheat flour with buttermilk at 30, 35 and 40°C for 6, 12, 18, 24 ad 48h significantly decreased the level of phytic acid; maximum decrease was observed at 40°C for 48h. Starch as well as protein digestibility (in vitro) improved with an increase in temperature and period of fermentation. Phytic acid had a significant (P<0.05) negative correlation with digestibility (in vitro) of both starch and protein ofrabadi.     

Effect of ensiling field bean, field pea and common vetch in different proportions with whole-crop wheat using formic acid or an inoculant on fermentation characteristics

Whole‐crop field bean (FB), field pea (FP) and common vetch (CV) [155, 213 and 238 g dry matter (DM) kg^?1] were ensiled in 1·5 L laboratory silos with whole‐crop wheat as mixtures of 0, 0·25, 0·50, 0·75 and 1·00 of fresh weight (FW). Silages were ensiled (i) without additive, and (ii) with formic acid (FA) (4 L t^?1) or (iii) an inoculant (Lactobacillus plantarum, 10⁶ colony‐forming units g^?1 FW) as additives. The concentrations of water‐soluble carbohydrates in herbage of whole‐crop FB, FP, CV and wheat were 93, 157, 67 and 114 g kg^?1 DM and the buffering capacities were 588, 710, 755 and 429 mEq kg^?1 DM respectively. Field bean and FP silages were mainly well preserved with low pH values and moderate fermentation losses, except for FB‐only silage without additive which had a high butyric acid concentration. Common vetch silages had higher pH values and were less well fermented compared to the silages of the other legumes. For all legumes, FA reduced ammonia‐N concentrations more effectively compared to other additive treatments. In conclusion, in FB and FP silages the use of FA or an inoculant, as additives, ensured good preservation up to a proportion of legume in the herbage of 0·75. With all legume silages, and with those containing CV, only FA, as an additive, adequately restricted protein breakdown.     

Trends of climatic potential and on-farm yields of rice and wheat in the Indo-Gangetic Plains

Rice and wheat are the two most important cereals in the Indo-Gangetic Plains (IGP) and are responsible for the food security of the region. To understand the productivity trends in the transects of the IGP: (1) the climatic potential yields of rice and wheat were simulated using a crop simulation modeling approach and (2) the long-term trends of potential and on-farm yields were compared. The potential yields of rice and wheat in the IGP ranged from 7.7 to 10.7 and 5.2 to 7.9 Mg ha⁻¹, respectively. The upper transects of the IGP are more productive and yield decreases by 27% for rice and by 32% for wheat from transect 2 to transect 5. The rate of change in the potential yield trend of rice from 1985 to 2000 ranged from −0.12 to 0.05 Mg ha⁻¹ per year. Negative yield trends were observed at six of the nine sites, four of which were statistically significant (P<0.05). The decrease in radiation and increase in minimum temperature were the reasons for the yield decline. The potential yield trend of wheat, however, appeared to be stable. On-farm yields of rice also showed a negative trend but for wheat the trend was mostly positive. The adverse changes in the weather parameters and declining trends of potential and on-farm yields of rice should be taken as an indication of a future problem. Regular on-farm monitoring of crops and climatic factors is urgently needed for predicting problems and allowing measures to be taken to improve productivity.     

Physicochemical properties of dry- and semi-wet-milled rice flours after fermentation by Lactobacillus amylovorus

Rice milling is one of the important factors that determines the physicochemical properties of rice flour. Dry milling is a simple and quick process, though it produces high levels of damaged starch that is not desirable in some application. Since fermentation can change the structure of starch as well as its physicochemical properties, the effect of fermentation on dry-milled rice flour was evaluated with the aim of improving flour quality for use as food ingredient in food industry. After fermentation at 37 °C for 24 h by Lactobacillus amylovorus, the dry-milled rice flour showed similar proximate compositions, physicochemical properties, and surface structures as semi-wet-milled rice products. Thus, the results suggest that it can be applied to produce desirable food materials for preparation of rice-based products.     

Extraction, preparation and characterization of cellulose fibres and nanocrystals from rice husk

Cellulose fibres and cellulose nanocrystals were extracted from rice husk. Fibres were obtained by submitting the industrial rice crop to alkali (NaOH) and bleaching treatments. Nanocrystals were extracted from these fibres using sulphuric acid (H₂SO₄) hydrolysis treatment. The material obtained after each stage of the treatments was carefully characterized and its chemical composition was determined. Morphological investigation was performed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fourier transform infrared (FTIR) spectroscopy showed the progressive removal of non-cellulosic constituents. X-ray diffraction (XRD) analysis revealed that the crystallinity increased with successive treatments. The thermal stability of the rice husk fibres and cellulose nanocrystals was also investigated using thermogravimetric analysis (TGA).     

Effect of heat treatment and germination on alpha amylase inhibitor activity in chick peas (Cicer arietinum L.)

Chick pea seeds of twenty eight varieties were analysed for alpha amylase inhibitor activity (AIA) using salivary amylase. The effects of heat treatment and germination on the activity of the antinutritional factor was investigated. Heat treatment and germination decreased the activity of amylase inhibitor. Chick pea meal was also subjected to UV irradiation and pressure cooking. These treatments decreased alpha amylase inhibitor activity. The amylase inhibitor activity decreased as the days of germination increased and negligible inhibitor activity was observed on the 6th day of germination.     

The effect of different additives on the fermentation quality, aerobic stability and in vitro digestibility of pea/wheat bi-crop silages containing contrasting pea to wheat ratios

Studies were conducted to compare the effects of using two microbial inoculants, a sulphite salt‐based additive, formic acid and quebracho tannins, on the fermentation quality, nutritive value and aerobic stability of pea/wheat bi‐crop silages. Spring peas (Pisum sativum var. Magnus) and spring wheat (Triticum aestivum var. Axona) were drilled together at rates that gave high (HP/W; 3:1) or low (LP/W; 1:3) pea to wheat ratios. The peas and wheat were harvested at the yellow wrinkled pods and late milk/early dough maturity stage, respectively, and conserved in 1·5‐kg polyethylene bag, laboratory silos. The bi‐crops were conserved without treatment (control) or treated with either of two lactic acid bacteria‐based inoculants [Lactobacillus buchneri; applied at 10⁵ colony‐forming units (CFU) g^–1 fresh weight (FW) or Lactobacillus plantarum (applied at 10⁶ CFU g^–1 FW)], sulphite salts (applied at the rate of 1 ml sulphite solution kg^–1 FW), quebracho tannins (applied at 16 g kg^–1 FW) and formic acid (applied at 2·5 g kg^–1 FW). Six replicates were made for each treatment, and the silos were opened after 112 days of ensilage. The level of peas in the bi‐crop influenced the effectiveness of the additives. With the exception of sulphite salts, all the additives significantly reduced the soluble nitrogen (N) and ammonia‐N concentrations of all the silages. The ratio of lactic acid to acetic acid was generally lower in the LP/W silages than in the HP/W silages, and the additive treatments only increased the in vitro digestible organic matter in dry matter of the LP/W silages. Of all the additives evaluated, formic acid resulted in the least aerobic spoilage in HP/W bi‐crop silages. However, in the LP/W bi‐crops, additive treatment was not necessary for ensuring aerobic stability.     

The effect of cultivar on the rate and extent of combining pea straw degradability examined in vitro using the Reading Pressure Technique

Although about 225 000 t dry matter (DM) pea straw is produced annually in the UK, no recent data exist with respect to its nutritive value when offered to ruminants. This study, to examine field pea crop waste (straw) from 12 commercial cultivars of combining peas, was therefore undertaken when material grown as part of a European field pea network trial at Reading in 1998 was made available. The straw was subjected to chemical analysis and examined in vitro using the Reading Pressure Technique to generate gas production profiles and to determine both rate and extent of DM and organic matter degradation. Ash and crude protein (CP) concentrations (69 and 65 g kg^–1 DM) were generally lower than published values for legume straws but higher, especially CP, than cereal straws. Neutral‐detergent fibre concentrations were slightly lower, and metabolizable energy (ME) values, derived from degradable organic matter assessed in vitro (iOMD), higher than cereal straws, ranging from 6·0 to 8·1 MJ ME kg^–1 DM. Both cumulative gas production and rate of gas release varied significantly between cultivars, as did degradation with 96‐h iOMD values ranging from 468 to 602 g kg^–1. By combining these with the quantity of material harvested, ME yields for the different cultivars were found to range from 15 to 27 GJ ME ha^–1. Considerable, and general highly significant, variation was found between the cultivars examined, which may be used to rank straws with respect to their nutritive value. The cultivars Baccara and Solara followed by Athos and Vital were readily ranked higher than the other cultivars in terms of in vitro fermentation parameters and ME yields. These data suggest that pea straw, although often incorporated into the soil in post‐harvest operations, shows excellent potential as a ruminant forage feedstuff.     

Dephytinization of wheat bran by fermentation with bakers' yeast,incubation with barley malt flour and autoclaving at different pH levels

Wheat bran is an important source of dietary fiber but also contains considerable amounts of phytic acid, which is known to impair mineral absorption. The present study was conducted to investigate the phytic acid reduction in coarse and fine wheat bran by fermentation with the different levels of bakers' yeast (3, 6 and 9%) for 8 h at 30 °C, incubation with the different levels of barley malt flour (2.5, 5.0, 7.5 and 10.0%) for 8 h at pH 5.2 and 55 °C, and autoclaving at the different pH levels (pH 5.0, 4.5, 4.0 and 3.5) adjusted with acetic acid for 2 h. The phytic acid content of the wheat bran was effectively reduced by all treatments, and the phytic acid lost was in the range of 88.4–96.9%. Without addition of yeast or malt flour, or autoclaving without pH adjustment, the phytic acid content of the bran samples was reduced at most to 44.9% of the initial amounts under the investigated conditions. Increasing the concentration of yeast or malt flour or decreasing the pH towards 3.5 did not enhance the phytic acid reduction. The most reduction occurred after 2 h of yeast fermentation and malt flour incubation, and after 30 min of autoclaving, which made up 92–98% of the total phytic acid loss. Extending the treatment periods contributed nominally to further increase in the phytic acid reduction, and the rate of the phytic acid loss decreased progressively.     

Agronomic,forage quality and economic advantages of red pea (Lathyrus cicera L.) intercropping with wheat and oat under low‐input farming

Red pea–cereal intercropping could provide animal feed with agronomic and economic advantages. The growth rate, forage yield, quality, interspecific competition and financial outcome of intercrops of red pea (Lathyrus cicera L.) with wheat (Triticum aestivum L.) and oat (Avena sativa L.) in two different seeding ratios (60:40, 80:20) were estimated. Growth rate of species was lower in the intercrops than in monocrops, especially in red pea–oat intercrops due to the strong competitive ability of oat. Red pea–oat intercrop of 60:40 produced the highest biomass (10.83 Mg/ha) and crude protein yield (1,116 kg/ha). Land equivalent ratio (LER) values were greater for the red pea with wheat (1.13) and oat 60:40 (1.09) indicating an advantage of intercropping in terms of dry‐matter (DM) yield, while red pea:oat 60:40 ranked first for LER for nitrogen yield. Aggressivity and partial actual yield loss indicated cereals as the dominant species. The highest monetary advantage index was recorded for the red pea:wheat 60:40 and the highest intercropping advantage value was recorded for the red pea:oat 80:20. In conclusion, most intercrops of red pea with wheat and oat showed significant advantages relative to their monocrops due to better DM production, resource‐use efficiency and economics under low‐input farming.     

PCR method for the detection and identification of cultivars of rice flours used in yeast leavened breads containing both wheat and rice flours

The identification of cereal grain sources in yeast leavened breads is challenging because of the mixtures of DNA from yeast and mixtures of related grains. DNA is decomposed during the fermentation and bread consists of not only rice but also wheat, yeast, sugar, butter, shortening etc.     

Changes in the physical and the sensorial properties of wheat bread caused by interruption and slowing of the fermentation of yeast-based leaven

Here we propose an original study on the effect of an interruption and slowing of the fermentation of yeast-based leaven on the physical properties of bread.     

Impact of ethanol,succinic acid,and the combination thereof at levels produced during sponge fermentation on hard wheat,soft wheat,and durum wheat farinograph rheology

The sponge and dough mixing process is one of the most common in the world, yet the mechanistic understanding of this process has yet to be sufficiently explored. In this study, aqueous solutions of ethanol, succinic acid, and their combination were prepared at concentrations intended to replicate fermentation times of 3, 4 and 6 h. These solutions were added to a farinograph mixer to make dough using hard wheat, soft wheat, and durum wheat flour. The results indicate that these yeast metabolites (ethanol, succinic acid) impact the mixing resistance, peak mixing value, and dough mixing stability in each of the flour types, likely primarily affected by the ratios of gliadin to glutenin and LMW glutenin in each flour type. Results suggest a stabilizing non-covalent interaction imparted by gliadin at peak mixing time, a stabilizing effect of HMW glutenin during break down, and synergistic effects of ethanol and succinic acid that leads to a faster rate of breakdown in later stages of mixing. It also suggests an increase in mixing resistance when acidulants are added to durum wheat dough. Taken together, this study adds new insights on the sponge and dough mixing process in a way that has not previously been conducted.     

Effect of jet-cooked wheat gluten/lecithin blends on maize and rice starch retrogradation

Vital wheat gluten and lecithin (GL) (50:50, w/w) were dry blended in a coffee grinder and a 9.5% (w/v) aqueous slurry was jet-cooked (steam pressures of 65 psi/g inlet and 40 psi/g outlet) to disaggregate wheat gluten and facilitate better dispersion of the two components. The jet-cooked material was freeze-dried and stored at 0 °C for future use. The GL blend was added to pure food grade common maize and rice starch at concentrations of 0 (control), 6, 11, 16, and 21%. Starch gelatinization and retrogradation temperature transitions were determined using Differential Scanning Calorimetry (DSC). From the DSC profiles, the change in the ΔH value was used as an indication of starch retrogradation, where a higher ΔH value indicated higher retrogradation. The ΔH values of the blends at 4 °C had higher values than the −20 °C and the ambient (25 °C) storage temperatures. Overall, the 21% GL/starch blends reduced retrogradation by 50%. The lower amylose content of rice starch relative to maize starch was reflected in Rapid Visco Amylograph (RVA) measurements of peak viscosity, and similarly, Texture Analyzer (TA) measurements indicated that maize starch gel is firmer than rice starch gel. Retrogradation was also evaluated by observing G′, the shear storage modulus, as a function of time after running a standard pasting curve. Using this method, it appears that GL has a significant effect on maize starch retrogradation, since low concentrations (<0.4%, w/w) reduced G′ up to 40%. The opposite behavior was seen in rice starch, where G′ increased directly with added GL. It appears that the amylose level in the rice starch is too low to be affected by the GL, and the increase seen in G′ is most likely due to added solids.     

Improvement of the quality and shelf life of wheat bread by fermentation with the antifungal strain Lactobacillus plantarum FST 1.7

Lactobacillus plantarum FST 1.7 was screened for in vitro antimicrobial activity and was shown to be active against spoilage moulds and bacteria. Isolation of antimicrobial compounds from cell-free supernatant identified lactic acid, phenyllactic acid and the two cyclic dipeptides cyclo (l-Leu-l-Pro) and cyclo (l-Phe-l-Pro) as the major components responsible for this activity. L. plantarum FST 1.7 was tested for the ability to produce the antifungal compounds during sourdough fermentation and to produce bread of good quality and increased shelf-life. A rheofermentometer was used to examine the gaseous release and development characteristics of the dough. A range of parameters was determined including pH, TTA and specific loaf volume. The results were compared with those obtained using Lactobacillus sanfranciscensis, a chemically acidified and a non-acidified dough. The quality of sourdough and bread produced using L. plantarum FST 1.7 was comparable to that obtained using common sourdough starters, e.g. L. sanfranciscensis. Sourdoughs and breads were evaluated for the ability to retard growth of Fusarium culmorum and Fusarium graminearum two fungi found on breads. Sourdough and bread produced with strain FST 1.7 showed consistent ability to retard the growth of both Fusarium species, thus indicating that L. plantarum FST 1.7 has also the potential to improve the shelf-life of wheat bread.     

Sourdough fermentation of wholemeal wheat bread increases solubility of arabinoxylan and protein and decreases postprandial glucose and insulin responses

Glycemic responses to most of the conventional breads are high, including breads made of wholemeal flour. Baking technology is known to affect these responses. The aim of the present study was to investigate effects of xylanase enzyme treatment and sourdough fermentation in wholemeal wheat bread baking on postprandial glucose and insulin responses and on in vitro protein digestibility. The wheat breads were made of 100% flour from peeled kernels by a straight dough or sourdough fermentation method, and with or without using xylanase during mixing of dough. Standard white wheat bread was used as a reference. All test bread portions contained 50 g available carbohydrate and were served in random order to eleven insulin resistant subjects. Blood samples for measuring glucose and insulin concentrations were drawn over 4 h. The sourdough wholemeal wheat bread resulted in the lowest postprandial glucose and insulin responses among the four tested breads (treatment × time; p = 0.000 and p = 0.022, respectively). There were differences in solubility and depolymerisation of protein and arabinoxylan among the breads but these did not fully explain the in vivo findings. In conclusion, the health effects of wholemeal wheat bread can be further improved by using sourdough process in breadmaking.     

Effect of natural fermentation on protein fractions and in vitro protein digestibility of rice

Seaweeds are rich sources of dietary fiber which possess diverse physiological functions in the colon. In the present study, the modulating effect of feeding seatangle (Laminaria japonica), a fiber-rich seaweed, on initiation and postinitiation of rat colon carcinogenesis was investigated. Four groups of animals were exposed to two weekly injections of a chemical carcinogen azoxymethane (AOM). Animals were fed a fiber-free semisynthetic diet or a diet containing 15% seatangle (4.7 g dietary fiber/100 g diet) during initiation, postinitiation or initiation postinitiation phase of carcinogenesis. Study results showed that animals fed the seatangle-containing diet had a significantly decreased number of both aberrant crypts and aberrant crypt foci in the colon. Also, labeling indices and proliferation zones were signi- ficantly reduced in the colon of the rats fed a seatangle diet. All of the seatangle feeding regimens used in this study were effective in reducing aberrant crypt formation indicating anticarcinogenic effects are mediated through both the blocking of initiation and the suppression of cell proliferation in initiated cells. These results suggest that a diet containing seatangle may decrease the risk of developing colon cancer although the precise cellular mechanisms involved in anticarcinogenic effects of seatangle should be further examined.