Wheat Germ

Wheat Germ Supplementation Reduces Inflammation and Gut Epithelial Barrier Dysfunction in Female Interleukin-10 Knockout Mice Fed a Pro-Atherogenic Diet

BACKGROUND

Mice lacking IL-10 are prone to gut inflammation. Additionally, decreased production of short-chain fatty acids (SCFAs) plays a significant role in the high-fat (HF) diet-induced loss of gut epithelial integrity. We have previously shown that wheat germ (WG) supplementation increased ileal expression of IL-22, an important cytokine in maintaining gut epithelial homeostasis.

OBJECTIVES

This study investigated the effects of WG supplementation on gut inflammation and epithelial integrity in IL-10 knockout mice fed a pro-atherogenic diet.

METHODS

Eight-week-old female C57BL/6 wild type mice were fed a control diet (10% fat kcal), and age-matched knockout mice were randomly assigned to 1 of 3 diets (n = 10/group): control, high-fat high-cholesterol (HFHC) [(43.4% fat kcal (∼49% saturated fat, 1% cholesterol)], or HFHC + 10% WG (HFWG) for 12 wk. Fecal SCFAs and total indole, ileal, and serum proinflammatory cytokines, gene or protein expression of tight junctions, and immunomodulatory transcription factors were assessed. Data were analyzed by 1-way ANOVA, and P < 0.05 was considered statistically significant.

RESULTS

Fecal acetate, total SCFAs, and indole increased (P < 0.05) by at least 20% in HFWG compared with the other groups. WG increased (P < 0.0001, 2-fold) ileal Il22 (interleukin 22) to Il22ra2 (interleukin 22 receptor, alpha 2) mRNA ratio and prevented the HFHC diet-mediated increase in ileal protein expression of indoleamine 2,3 dioxygenase and pSTAT3 (phosphorylated signal transducer and activator of transcription 3). WG also prevented the HFHC diet-mediated reduction (P < 0.05) in ileal protein expression of the aryl hydrocarbon receptor and the tight junction protein, zonula occludens-1. Serum and ileal concentrations of the proinflammatory cytokine, IL-17, were lower (P < 0.05) by at least 30% in the HFWG group than in the HFHC group.

CONCLUSIONS

Our findings demonstrate that the anti-inflammatory potential of WG in IL-10 KO mice consuming an atherogenic diet is partly attributable to its effects on the IL-22 signaling and pSTAT3-mediated production of T helper 17 proinflammatory cytokines.

Investigation of sorption isotherms of wheat germ for its effect on lipid oxidation

This research aimed to investigate the oxidation and sorption isotherm properties of wheat germ and to determine monolayer moisture content (m₀ ) in particular, because it has a limiting effect on lipid oxidation. This research comprised two stages. The first stage was the determination of sorption properties and m₀ at three temperatures (15, 25, and 35°C). The second stage of the research was to investigate lipid oxidation properties of stored wheat germ at two different temperatures (4 and 25°C) and m₀ for 28 days. As a result, it was determined that wheat germ has a Type II sorption isotherm, Halsey is the best fitting sorption equation, and the average m₀ is 4.25 g moisture per 100 g dry matter. Furthermore, the free fatty acid and peroxide value of wheat germ oil increased with increasing storage moisture content and temperature, determined as 12.63% and 5.01 mEqO₂ /kg on average, respectively. In conclusion, storage of impermeably packaged wheat germ at low temperature and m₀ content is an applicable method for decreasing rancidity and prolonging shelf-life.

Protective effects of wheat germ oil against erectile and endothelial dysfunction in streptozotocin-induced diabetic rats

Our aim was to investigate the protective effect of wheat germ oil (WGO) at different doses on diabetes mellitus (DM)-induced erectile and endothelial dysfunction. Twenty-four male Wistar rats weighing 250-300 g were divided into four groups as; control group treated with saline, DM group, DM group treated with 3 ml/kg WGO (DM + 3WGO group), DM group treated with 6 ml/kg WGO. Type 1 DM was induced by intraperitoneal injection of 60 mg/kg streptozotocin (STZ). STZ-induced diabetic rats received saline, 3 ml/kg WGO, and 6 ml/kg WGO via oral gavage daily for 5 weeks. The density of WGO used was 0.92 g/ml. The protective effect of WGO was evaluated by (i) in vitro vascular function, (ii) in vivo erectile function, and (iii) oxidative stress parameters in both aorta and penile tissue. Acetylcholine-mediated relaxation in the aorta and erectile functions decreased significantly in the DM group (p = 0.018 and p = 0.005). WGO (3 and 6 ml/kg) improved vascular functions in the DM groups (p = 0.001 and p = 0.014). The beneficial effect of WGO on erectile function appeared at higher doses of WGO. However, a higher dose of WGO substantially increased the oxidative stress parameters in both aorta and penile tissue. These findings suggest that the improvement in vascular or erectile function by WGO was not related to antioxidant effects, and new studies are needed to clarify the mechanism.

Wheat germ stabilization by infrared radiation

Wheat germ has an important enzymatic activity, being lipases the enzymes which cause the highest impact in the reduction of shelf life. The objective of this study was to evaluate the effects of infrared radiation on wheat germ stabilization in an attempt to extend the shelf life. The effects of treatment time, gap (sample distance to IR emitters) and infrared radiation intensity on wheat germ were analyzed through response surface methodology. Final moisture content, final temperature, color of germ and germ oil quality parameters: free fatty acid content changes and total tocopherol content were the responses evaluated using a Box-Behnken design. A combination of an infrared radiation intensity of 4800 W/m², a 3 min treatment and 0.2 m emitter-sample distance were the best processing condition to stabilize the wheat germ without significantly reduction of the tocopherol content. A confirmatory experiment was conducted with these optimal conditions, and the heat-treated and raw germ samples were stored for 90 days at room temperature in three layer packages to protect them against light and oxygen. The oil quality parameters indicated that the raw germ had a shelf-life of about 15 days, with the heat-treated wheat germ maintaining its quality for at least 90 days under these stored conditions.

Molecular mechanisms of the protective role of wheat germ oil against cyclosporin A-induced hepatotoxicity in rats

CONTEXT

Cyclosporin A (CsA) is one of the most important immunosuppressive agents. However, its clinical use is strongly limited by several side effects including hepatotoxicity which remains a major clinical problem. Involvement of reactive oxygen species (ROS) in CsA-induced hepatotoxicity has been reported.

OBJECTIVE

This study investigates the potential protective role of wheat germ oil (WGO) as an antioxidant against CsA-induced hepatotoxicity.

MATERIALS AND METHODS

Twenty-four male Wistar albino rats (six animals in each group) received castor oil, the vehicle of CsA i.p. (control) or either CsA (25 mg/kg/d i.p.), WGO (900 mg/kg/d by oral gavage), or CsA in combination with WGO daily for 21 d.

RESULTS

CsA administration significantly increased serum levels of the liver enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST). In addition, an increase in lipid peroxidation, inducible NO-synthase (iNOS), and NF-κB expression were observed in hepatic tissues of CsA-alone-treated rats. Furthermore, significant reduction in the hepatic content of reduced glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) was also observed in CsA-alone-treated animals. Moreover, histopathological changes occurred in CsA-alone-treated rats. Concomitant administration of WGO along with CsA improved all these parameters. Most interestingly, the immunosuppressive effect of CsA was not affected by WGO.

CONCLUSION

The present study suggests that concomitant use of WGO might be useful in reducing liver toxicity induced by CsA via inhibition of ROS, iNOS, and NF-κB expression.

Influence of wheat germ and β-glucan on some chemical and sensory properties of Turkish noodle

Wheat flour used in Turkish noodle (erişte) production was replaced with wheat germ (0, 10, 20 and 30 %) and β-glucan (0 and 4 %). Noodle samples were analyzed for their moisture, ash, protein, fat, mineral contents, color values and sensory properties. Cooking properties as volume increase (VI), weight increase (WI) and cooking loss (CL) were also determined. Wheat germ increased the ash, protein, fat and mineral contents of the noodles. β-glucan had an improving effect especially on Ca, Fe, Mg and P contents of noodle samples. While wheat germ raised VI values of the noodle, β-glucan had a negative effect on VI. The CL of noodle samples varied between 5.8 % and 7.3 %. Decreasing sensory scores obtained at high level of wheat germ with and without β-glucan. The present results showed that wheat germ and β-glucan have a good potential for increasing nutritional quality of noodle.

New hypotheses for the health-protective mechanisms of whole-grain cereals: what is beyond fibre?

Epidemiological studies have clearly shown that whole-grain cereals can protect against obesity, diabetes, CVD and cancers. The specific effects of food structure (increased satiety, reduced transit time and glycaemic response), fibre (improved faecal bulking and satiety, viscosity and SCFA production, and/or reduced glycaemic response) and Mg (better glycaemic homeostasis through increased insulin secretion), together with the antioxidant and anti-carcinogenic properties of numerous bioactive compounds, especially those in the bran and germ (minerals, trace elements, vitamins, carotenoids, polyphenols and alkylresorcinols), are today well-recognised mechanisms in this protection. Recent findings, the exhaustive listing of bioactive compounds found in whole-grain wheat, their content in whole-grain, bran and germ fractions and their estimated bioavailability, have led to new hypotheses. The involvement of polyphenols in cell signalling and gene regulation, and of sulfur compounds, lignin and phytic acid should be considered in antioxidant protection. Whole-grain wheat is also a rich source of methyl donors and lipotropes (methionine, betaine, choline, inositol and folates) that may be involved in cardiovascular and/or hepatic protection, lipid metabolism and DNA methylation. Potential protective effects of bound phenolic acids within the colon, of the B-complex vitamins on the nervous system and mental health, of oligosaccharides as prebiotics, of compounds associated with skeleton health, and of other compounds such as alpha-linolenic acid, policosanol, melatonin, phytosterols and para-aminobenzoic acid also deserve to be studied in more depth. Finally, benefits of nutrigenomics to study complex physiological effects of the 'whole-grain package', and the most promising ways for improving the nutritional quality of cereal products are discussed.

Effect of thermal processing on the nutritive value of wheat germ protein

Wheat germs are used as industrial products for nourishment so that it was necessary to determine the nutritive value of proteins in raw and in roasted wheat germs (temperature: 130-150 degrees C for 20 min). Protein quality evaluation has been determined by a biological method--feeding young growing rats. The rats were fed 10% level protein diets, based on raw and roasted wheat germs. The results show that protein of roasted wheat germs has higher digestibility (D) and protein efficiency ratio (PER) than the raw wheat germs which proves that roasting destroyed digestion enzymes inhibitors. Furthermore, the net protein utilization (NPU) has also been improved by roasting. Biological value (BV) of raw germs approximates to the value of roasted germs. The results lead us to the conclusion that roasting saves and improves protein parameters in wheat germs.

Composition of cereal germ preparations

Germ from wheat, rye, triticale, barley and oat was prepared by passing the grain through an Entoleter impact mill. The content of a number of important nutrients in the germ preparations was determined in order to make a preliminary evaluation of the potential use of these preparations as food ingredients. alpha-Tocopherol, polyunsaturated lipids, protein, threonine, methionine, lysine, raffinose, sucrose, thiamin and riboflavin were chosen since these are the components regarded as most important in commercial wheat germ. All the germ preparations had compositions essentially similar to published values for commercial wheat germ derived from flour milling. The germ lipids of rye and triticale had a very high content of linolenic acid which could lead to problems of oxidative rancidity. Otherwise, the germ preparations appear suitable as an alternative to commercial mill gem for food ingredient applications.