Isolation and properties of lipolysis inhibitory proteins from wheat germ and wheat bran

Proteins inhibiting pancreatic lipasein vitro have been isolated from wheat germ and wheat bran, with relative molecular mass ranging from 24,400 to 27,500. Inhibition of pancreatic lipase by the wheat germ proteins is related to their ability to interact with the emulsified substrate and to hinder the adsorption of the enzyme on the interface. The extent of inhibition depends on the amount of substrate and is independent of the enzyme concentration. Bile salts forming micelles in the concentration range used are able to partially reverse the inhibition of pancreatic lipase by the wheat germ proteins. The nutritional significance of the data obtained is discussed.     

Optimization of ultrasound-assisted extraction of defatted wheat germ proteins by reverse micelles

In this work, an ultrasound-assisted procedure for the extraction of defatted wheat germ proteins by reverse micelles was established. Response surface methodology (RSM) was used to optimize the ultrasound-assisted extraction (UAE) parameters (ultrasonic output power, ultrasonic time and pulse mode) for enhancing the forward extraction efficiency of defatted wheat germ proteins by implementing a three-level, three-variable Box–Behnken experimental design. The independent variable with the largest effect on response was X₂ (ultrasonic time), followed by X₁ (ultrasonic output power) and X₃ (pulse mode). The optimum extraction conditions were found to be ultrasonic output power 363 W, ultrasonic time 24 min and pulse mode 2.4 s on and 2 s off (2.4 s:2 s). Under these conditions, the forward extraction efficiency of defatted wheat germ proteins can increase from 37% to 57%, and the final protein extraction efficiency by reverse micelles can reach 45.6%, making the advantage of reverse micelles much more obvious than alkaline extraction and isoelectric precipitation on the separation of protein.     

Protein extraction from defatted wheat germ by reverse micelles: Optimization of the forward extraction

In this work, the forward extraction of defatted wheat germ protein (DWGP) by reverse micelles was studied. The reverse micellar systems were formed by sulphosuccinic acid bis (2-ethylhexyl) ester sodium salt (AOT), isooctane and KCl solution. The effects of AOT concentration, pH, KCl concentration, extraction time, the amounts of defatted wheat germ flour (DWGF), W₀ (the molar ratio of water to surfactant, i.e. W₀ = [H₂O]/[AOT]) and temperature on the forward extraction efficiency of DWGP were tested. On the basis of single-factor experiments, the optimum extraction was achieved by response surface methodology (RSM). The experimental results lead to the conclusion that the highest forward extraction efficiency of DWGP was reached at the AOT concentration 0.06 g/mL, pH 8, KCl concentration 0.1 mol/L, time 30 min, the amounts of DWGF 0.500 g, W₀ 25 and temperature 36 °C. Under these conditions, the forward extraction efficiency of DWGP achieved 37%.     

Health effects of wheat lectins: A review

Lectins are carbohydrate-binding proteins present in most plants. They play a role in protecting plants against external pathogens, like fungi, and other organisms. Some common dietary staples, such as cereal grains and legumes, have relatively high concentrations of a variety of lectins. A part of the proteins present in wheat germ is characterized as wheat germ agglutinin (WGA), in this respect. Authors of popular nutritional plans propose adverse health effects of this wheat lectin. With the use of different arguments, the consumption of foods high in lectins is discouraged. In this context, we discuss the effects of lectins from wheat on human health. Up-to-date research findings on mechanisms that wheat lectins have effects on health factors, such as obesity, autoimmune disease, and celiac disease, are critically reviewed. We conclude that there are many unsubstantiated assumptions made. Current data about health effects of dietary lectins, as consumed in cooked, baked, or extruded foods do not support negative health effects in humans. In contrast, consumption of WGA containing foods, such as cereals and whole grain products, has been shown to be associated with significantly reduced risks of type 2 diabetes, cardiovascular disease, some types of cancer, as well as a more favourable long-term weight management. Research is recommended to define actual active lectin contents in wheat-based foods after heat preparation for human consumption.     

云南不同生态环境对硬粒小麦品质的影响

选用云南生产上种植的硬粒小麦品种“780”为材料，通过3个不同生态试点、两种栽培方式对硬粒小麦籽粒品质性状影响的研究得出：在相同栽培条件下，蛋白质含量、湿面筋含量、沉隆值、形成时间、评价值、耐揉指数等随海拔高度的升高面升高，出粉率、吸水率等随海拔高度的升高而降低，稳定时间、弱化度、和面时间、断裂时间等表现为中海拔高于低海拔、高海拔。总的来看，硬粒小麦品质性状表现为田麦栽培方式优于地麦栽培方式。     

Effect of wheat bran supplementation on blood sugar,glycosylated protein and serum lipids in NIDDM subjects

Wheat bran supplementation (11 gm per day) was carried out for a period of two months in 30 maturity onset diebetics. The efficacy of bran supplementation was monitored by measuring the fasting and 2 h post prandial blood sugar levels, glycosylated serum protein levels, glycosylated albumin levels and serum lipid and lipoprotein cholesterol levels. The results indicated a transient reduction in fasting and 2 h post prandial blood sugar levels after one month's bran therapy. No appreciable changes in the serum glycosylated protein levels, glycosylated albumin levels, serum lipids and lipoprotein cholesterol levels were observed during the period of supplementation.Abbreviations TC total cholesterol - HDL-C high density lipoprotein cholesterol - LDL-C low density lipoprotein cholesterol - VLDL-C Very low density lipoprotein cholesterol - TG triglycerides - PL phospholipids - FFA free fatty acids - G-Alb glycosylated albumin - GSP glycosylated serum proteins - NIDDM Non Insulin Dependent Diabetes Melitus     

Effect of boiled barley-rice-feeding in hypercholesterolemic and normolipemic subjects

Barley contains approximately 10% dietary fiber and is easily cooked with rice, the dominant cereal in Japan, to increase the intake of dietary fiber. This research involved three experiments to examine the influence of barley on blood lipids in human subjects. All subjects received a boiled barley-rice (50/50 w/w mix) supplement two times per day in place of rice for 2 or 4 weeks. In the normolipemic subjects, serum lipids were unaffected by the ingestion of barley for 4 weeks. In twenty hypercholesterolemic men aged 41 ± 5 years, the ingestion of barley was associated with a significant fall in serum total cholesterol, LDL-cholesterol, phospholipids and LDL and VLDL-lipoproteins. In seven mildly hypercholesterolemic women aged 56±7 years, a significant improvement of serum lipid profiles was observed. The present study suggests the possibility that the ingestion of barley-rice could lower serum lipids in hypercholesterolemic subjects.     

Immunomodulatory activities of non-prolamin proteins in wheat germ and gluten

Albumin (Alb), globulin (Glo), glutelin (Gll) and glutenin (Gln) were separately extracted from wheat germ and wheat gluten. Amino acisd composition, molecular weight distribution, solubility, in vitro digestibility, and immunomodulatory activities were all analyzed. Gll and Gln have similar molecular weight distributions, which differed from those of Alb and Glo. Alb showed the highest solubility at various pH values (except pH 4.0), whereas Glo showed the highest in vitro digestibility. Glo and Gll have the highest proportion of essential to total amino acids, while Alb and Gll have the highest protein digestibility-corrected amino acid scores. Gll had the strongest immunomodulatory effects in terms of stimulation of RAW 264.7 cells to produce IL-6, TNF-α, and IL-10, and good stimulatory effects on splenocyte proliferation, production of IL-2, phagocytosis, and secretion of nitric oxide in RAW 264.7 cells. Gll can be considered a good protein source for use in health foods.     

Computational Assessment of Chito-Oligosaccharides Interactions with Plasma Proteins

It is widely rec ognized that chitin and chitosan are potential sources of bioactive materials and that their oligosaccharides reveal various biological activities (including antimicrobial) that are correlated with their structures and physicochemical properties. This study uses the molecular docking approach to assess the interactions of small chito-oligosaccharides (MW< 1500 Da) with plasma proteins in order to obtain information regarding their fate of distribution in the human organism. There are favorable interactions of small chito-oligomers with plasma proteins, the interactions with human serum albumin being stronger than those with α-1-acid glycoprotein. The interaction energies increase with increasing the molecular weight, decrease with increasing deacetylation degrees and are reliant on the deacetylation pattern. This study could inform the application of chito-oligosaccharides with varying molecular weights, degrees, and patterns of deacetylation in human health.     

Genetic improvement effects on yield stability in durum wheat genotypes grown in Italy

In durum wheat (Triticum durum Desf.) the improvement of yield stability represents an important component for agricultural progress worldwide. This work reports on the evaluation of the yield performance of 65 durum wheat genotypes (landraces, old and new cultivars with different years of release and advanced breeding lines), in a range of Italian environments to assess the changes in adaptation and yield stability achieved over the last century as results of the genetic improvement. The Additive Main effect and Multiplicative Interaction (AMMI) analysis was used to capture a large portion of the Genotype × Environment interaction (GE) sum of squares and to separate main and interaction effects. The breeding strategies adopted during the last decades have contributed to reduce the interaction of genotypes with environments selecting genotypes with better stability across a wide range of locations and years and modern genotypes outperformed the old ones in all test environments with a strong adaptability to improved fertility. The old cultivars were characterized by a minimal responsiveness to improved environmental conditions, showing an almost stable nominal yield in agreement with the concept of “biological” or “static” stability. In contrast, the modern cultivars were highly responsive to fertility improvements and showed a pronounced adaptation to high-input environments. Notably, within the group of modern cultivars two of them, Tiziana and Giusto, showed a high-yield stability in biological terms and a high nominal yield across the tested environments. Giusto and Tiziana were the best cultivars in terms of both nominal yield and minimal GE interaction, indicating that selecting for improved yield potential may increase yield in a wide range of environments.     

Effect of lowering the root/shoot ratio by pruning roots on water use efficiency and grain yield of winter wheat

A pot and a field experiment were conducted to assess the effects of root/shoot ratio (R/S) on the water use efficiency (WUE) and grain yield of winter wheat. The R/S was regulated by pruning the roots during the stem elongation stage, resulting in reduced root systems of the plants. At the heading stage, the root dry weight of root-pruned plants was less than that of intact-root plants, but their R/S was similar to that of intact-root plants under both experimental conditions. After tiller pruning, the R/S of root-pruned plants was significantly lower than that of intact-root plants (p < 0.05). Root pruning reduced the rate of leaf transpiration and lowered the number of tillers per plant (p < 0.05) during the vegetative stage. As a result, root-pruned wheat showed reduced water use when compared to intact-root plants before heading (p < 0.05). At anthesis, there was no significant difference in transpiration between plants with intact roots and those with pruned roots in the pots. However, under field conditions, transpiration of root-pruned plants was significantly higher than that of intact-root plants at anthesis. Additionally, at anthesis root-pruned plants had a higher rate of leaf photosynthesis and lower rate of root respiration, which resulted in a significantly higher grain yield at maturity when compared to plants with intact roots. Under both experimental conditions, there were no significant differences in shoot dry weight per plant between root-pruned and intact-root plants grown in monoculture. When root-pruned plants were grown with intact-root plants, the root-pruned wheat was less productive and had a lower relative shoot dry weight (0.78 and 0.86, respectively) than the intact-root plants (1.24 and 1.16, respectively). These results suggest that plants with pruned roots had a lower ability to compete and to acquire and use the same resources in the mixture when compared with intact-root plants. Root pruning improved the WUE of winter wheat under both experimental conditions. This suggests that appropriate management for the root system/tillers in wheat crops can be used to increase grain yield and water use efficiency. Specifically, lowering the R/S improved the grain yield and WUE of winter wheat significantly by lowering its competitive ability and improving root efficiency. Therefore, drought-resistance breeding to improve the grain yield and WUE, at least for wheat, should be made by targeted selection of less competitive progeny with a small R/S for cultivation in arid and semiarid areas.     

Effect of wheat germ flour addition on wheat flour,dough and Chinese steamed bread properties

Wheat germ flour (WGF) has been developed as a functional food ingredient with high nutritional value. In this study, WGF was applied in steamed bread-making in order to improve the quality of Chinese steamed bread (CSB). Partial substitution of wheat flour with WGF at levels of 3%, 6%, 9% and 12% (w/w) was carried out to investigate physicochemical properties of blends and their steaming performance. Falling number (FN) values of composite flours ranged from 199 to 223 s. Viscosity analysis results showed that wheat flour mixed with WGF had higher pasting temperature and lower viscosities. Dough rheological properties were also investigated using farinograph and extensograph. The addition of WGF diluted the gluten protein in dough and formed weak and inextensible dough, which can be studied by scanning electron microscope (SEM) analysis. CSB made with WGF had significantly lower volume, specific volume and higher spread ratio. The sensory acceptability and physicochemical quality of CSB were improved with the application of a low level of WGF (3% and 6%). However, results showed that a high level of WGF over 9% is not recommended because of unsatisfactory taste. As a whole, addition of appropriate level of WGF in wheat flour could improve the quality of CSB.     

Combined effects of glucose oxidase,papain and xylanase on browning inhibition and characteristics of fresh whole wheat dough

In this study, a glucose oxidase (GOX), papain and xylanase combination was developed for fresh whole wheat dough for both browning inhibition and rheological improvement. Measurements of carotenoids extracted from enzyme-treated doughs showed that 0.001% (w/w) GOX could catalyze the oxidization of 40.0% carotenoids and thus cause a decrease of browning index (BI) by 5.20 during dough preparation. For 24 h browning inhibition, 0.010% (w/w) xylanase and papain individuals were able to separately act on the phenolic compounds and polyphenol oxidase, leading to lower BI rises (5.36 and 7.04, respectively) of doughs as compared to the BI rise (13.53) of the control dough; however, 0.020% GOX caused a higher BI rise (16.60) than control although it made BI decrease by 6.34 at 0 h. Rheological investigations on enzyme-treated doughs revealed that both xylanase and papain led to decreases of elastic (G′) and viscous modulus (G″) of doughs while GOX caused increases of G′ and G″. Therefore, an optimal combination composed of 0.010% (w/w) xylanase, 0.005% (w/w) papain and 0.002% (w/w) GOX was carried out using orthogonal experimental design by comparing BI rises in 24 h, which was also proved as a rheological improver for fresh whole wheat dough.     

Characterization and comparison of predominant aroma compounds in microwave-treated wheat germ and evaluation of microwave radiation on stability

The present study was performed to evaluate the effects of microwave (MW) output power and treatment time on moisture content, lipase and lipoxygenase activities as well as colour changes of wheat germ (WG). In addition, the key aroma compounds in different MW-power-treated WG, which is of importance to the flavour of WG products, were also investigated. The obtained results showed that MW treatment maintained the inherent colour of WG and significantly reduced the moisture content (maximum reduction of 95%) and the activities of lipase and lipoxygenase (maximum reduction of 65% and 99%, respectively). In terms of aroma compounds, with the increase of the MW output power, the content of esters, alkanes, alcohols and acids decreased, while the content of heterocyclic compounds, nitrogen-containing compounds, aldehydes and ketones increased, providing more compounds with roasted flavour and less volatiles with grass-like flavour. Therefore, MW treatment was an effective stabilization method for WG utilization.     

Phenolics in the bran of waxy wheat and triticale lines

The present study was designed to determine total phenolic acid contents (TPC) and compositions of bran from newly developed near-isogenic waxy wheat and triticale translocation lines. Two waxy wheat sets, Svevo (durum) and N11 (bread wheat), consisting of partial and waxy null lines and four sets of triticales (GDS7, Trim, Rhino and Rigel) having translocations at 1A.1D and 1R.1D with high molecular weight glutenin subunits (HMW-GS) 5 + 10 and 2 + 12 were investigated. Similar to non-waxy wheat, ferulic acid was the predominant phenolic acid found in waxy wheats analyzed. Two other major phenolics include p-coumaric and vanillic acids followed by lesser quantities of syringic acid. Waxy lines had higher TPC than the parent line in the N11 set, whereas the Svevo set showed the opposite trend. TPC of waxy bread wheats were correlated with amylose fractions in which the order was complete waxy < double waxy nulls < single waxy nulls. Lines with HMW-GS 2 + 12 have lower TPC than other lines in each group of triticales, except the Trim set. TPC was negatively correlated (r = −0.41; p > 0.1) with bran yields in triticale lines studied, indicating that variation in phenolics was not only due to bran yields but also to genotypic differences.     

Distribution along durum wheat kernel of the components involved in semolina colour

A bright yellow colour of pasta is an important qualitative trait for the durum wheat industry. Final colour is the result of the balance between yellow and brown components in semolina. Carotenoid pigments and lipoxygenase (LOX) enzyme are mainly involved in yellowness, whereas peroxidase (POD) and ash affect brown hue. All these components have a different distribution across the kernel, with varietal differences too. This study aimed to evaluate the distribution pattern of carotenoid pigments, α-tocopherol, linoleic acid, and ash content as well as of LOX and POD activities within the kernel of six durum wheat cultivars characterised by different pigment content and hydroperoxidation activity of LOX in semolina. The results confirmed differences in the distribution of these components across the kernel and among varieties. Additionally, this study identified for some components (POD, pigments and bleaching activity of LOX) a higher effect of genotype whereas for others (ash, α-tocopherol, hydroperoxidation activity) a marked effect of the debranning process. These results suggest that improvement of the final semolina colour could be reached both through breeding activity, enabling an early selection of better lines, and through an appropriate debranning process.     

Evaluation of CIMMYT conventional and synthetic spring wheat germplasm in rainfed sub-tropical environments. I. Grain yield

Hexaploid spring wheat (Triticum aestivum L.) germplasm from CIMMYT's breeding program in Mexico has assisted wheat improvement in Australia, particularly in the north-eastern region where terminal drought frequently reduces grain yield. A total of 273 conventional hexaploid and derived synthetic hexaploid spring wheats from CIMMYT, along with 15 locally adapted Australian cultivars (Oz lines), were evaluated for grain yield over four years in a total of 27 environments in Australia's north-eastern wheat region. The CIMMYT conventional spring wheats were from a Seri/Babax recombinant inbred line population (SB lines), elite entries from an International Adaptation Trial (IAT lines) introduced to Australia between 1999 and 2004 and from CIMMYT screening nurseries introduced to Australia in 2004–2005 (SW lines). Synthetic wheats (SYN lines) were also from these nurseries as well as from a separate program of synthetic wheat introductions to Australia over 2001–2004.     

Glycemic index of grain amaranth, wheat and rice in NIDDM subjects

Glycemic index of grain amaranth, wheat and rice preparations was studied in noninsulin dependent diabetic subjects. Diets containing 50 g carbohydrate equivalent were given and post-prandial blood glucose estimated at different intervals. Glycemic index calculated for different experimental diets showed that GI of amaranth-wheat composite flour diet (25∶75) was the least (65.6%) followed by wheat diet (65.7%), rice diet (69.2%), amaranth-wheat flour 50∶50 (75.5%), and popped amaranth in milk (97.3%). Therefore 25∶75 combination of amaranth and wheat, wheat and rice can be considered low GI food, 50∶50 grain amaranth and wheat medium GI food and popped amaranth and milk combination high GI food.     

Determination of wheat bug (Eurygaster spp.) damage in durum wheat (Triticum durum L.) by electrophoresis and rapid visco analyser

The degradation effects of wheat bug protease(s) on glutenin proteins of durum wheat cultivars were investigated by electrophoresis and modified rapid visco analyser (RVA) test. Glutenin patterns of the bug damaged durum wheats changed substantially due to bug protease(s). Although high molecular weight glutenin subunits (HMW-GS) of three cultivars (Ege, Svevo, and Zenith) disappeared after 60 min of incubation, the HMW-GS of other two cultivars (Diyarbakir and Firat) were still visible even after the longest incubation period at medium damage level. It shows that there was an intercultivar variation in susceptibility to hydrolysis by bug proteolytic enzymes. Low molecular weight glutenin subunits of all cultivars decreased substantially after 30 min of incubation. The RVA curves indicated a clear reduction in viscosity in semolina samples with both medium and high damage levels as compared to their respective undamaged (control) samples. There were significant correlations (p < 0.001) between bug damage level and viscosities at 3 min (r = −0.765), at 4.5 min (r = −0.549) and at 10 min (r = −0.835), breakdown value (r = −0.534) and decay rate (r = 0.600). Consequently, hydrolysis rate of wheat bug protease(s) can be determined by modified RVA technique without much more chemicals, procedures and expensive equipments.     

The use of genetics in understanding protein composition and grain quality in wheat

As each of the classes of wheat-grain protein has been implicated in some aspect of man's interest in wheat utilization, we are motivated to learn more about the genetic control of their synthesis so that breeders may better tailor wheats to specific requirements. The gliadins have particularly merited study because they appear to be responsible for coeliac condition and for depressed lysine content, and as they are proving valuable for varietal identification and grain-quality prediction. Genetic aspects of gliadin synthesis have been studied using aneuploids, by examining F₁ and F₂ segregation after crossing, and by computer comparison of the gliadin composition of many genotypes in conjunction with systematic pedigree comparisons. These studies indicate gliadin synthesis to be controlled by blocks of tightly linked genes on the short arms of the chromosomes of groups 1 and 6. The high molecular weight subunits of glutenin are genetically distinct from the gliadins, being coded by genes on the long arms of chromosomes 1A, 1B and 1D. A better understanding of the relationship between grain quality and specific endosperm proteins is now developing. It is likely to provide simpler means of selecting for quality type in both breeding and harvest segregation.