Quality Evaluation of Wheat Germ Cake Prepared with Different Emulsifiers

Impact of xylanase-treated wheat milling by-products on the physical and chemical properties of cakes

BACKGROUND

Wheat milling by-products (germ and bran) are rich in dietary fiber, protein, vitamins, minerals and antioxidants. In this study, wheat milling by-products (bran obtained by debranning (BOD), coarse bran, fine bran and wheat germ) were used in the production of cake at different ratios (0-30%) after treatment with xylanase. Xylanase was used to improve the technological properties of the by-products and thus improve end-product quality.

RESULTS

As the by-products ratio increased in cake formulation, ash, protein, fat, crude fiber, phytic acid and mineral content significantly (P < 0.05) increased. In terms of by-product type, phytic acid content of the cakes changed between 1.14 and 2.55 g kg^-1 , and the lowest value was obtained in cakes prepared with BOD. The highest protein, Mn and Zn contents were found in cake samples containing wheat germ, whereas the addition of BOD revealed greater crude fiber, Ca and Fe levels in cake samples than the other by-products. Xylanase treatment resulted in increments in volume and decrements in hardness and color lightness values of cakes.

CONCLUSION

This study demonstrated that the use of the wheat by-products after treatment with xylanase had an improving effect on the quality and nutritive value of cakes. The results obtained in this study provided a basis for the use of xylanase in enriched cake production. © 2021 Society of Chemical Industry.

Effect of orange-fleshed sweet potato flour particle size and degree of wheat flour substitution on physical, nutritional, textural and sensory properties of cookies

Orange-fleshed sweet potato (OFSP) flour is rich in health-promoting compounds that can improve the nutritional benefits of baked products when blended with wheat flour. However, the flour particle size and blend proportion may affect the quality properties and consumer acceptability of bakery products. This study investigated the effect of flour particle sizes and blend proportions on the physical, nutritional, textural and sensory properties of peeled and unpeeled OFSP composite flour cookies. Peeled and unpeeled OFSP flours (≤ 250 μm and ≤ 500 μm particle size) were produced, and each was used to replace soft wheat flour at the rate of 0 to 100% for cookies formulation. The results obtained showed that substitution of wheat flour with OFSP flours significantly (p < 0.05) decreased cookies baking loss, thickness, volume, crust lightness (L*) but increased diameter, spread ratio, crust redness, yellowness, contents of ß-carotene, vitamin A, ascorbic acid, total phenolics and flavonoids, and the antioxidant capacity. The hardness and fracturability of the OFSP-based cookies ranged between 1.389 and 10.142 kg and 0.873 and 9.431 kg, respectively, whereas the values of the control cookies were 1.281 ± 0.003 kg and 1.274 ± 0.003 kg, respectively. The effect of flour particle size on the physical and nutritional properties of cookies was insignificant (p > 0.05). However, the ≤ 250 μm particle size flour cookies had higher overall acceptability than the ≤ 500 μm particle size flour cookies. The unpeeled OFSP composite cookies had higher bioactive compounds concentrations except for ascorbic acid but had lower overall acceptability than the peeled OFSP cookies. Generally, the 30% peeled OFSP composite flour cookies had the highest consumer acceptability.

Wheat germ oil nanoemulsion for oil stability of the cooked fish fillets stored at 4 °C

Production of wheat germ oil nanoemulsions (WGO), having 114.7 nm average zeta size, 0.144 PD index, 14.76 mV zeta potential value, were successfully carried out. TBARS, FFA, PV, CD, and CT tests, lipid nutritional quality indexes (AI, HH, PI, TI, EPA/DHA, PUFA/SFA, and n3/n6), color measurements, and the changes in sensory quality were studied in cooked mackerel fillets stored at 4 °C for 11 days. WGO nanoemulsion has delayed the increase in TBARS, FFA, PV, CD, and CT values of cooked fish fillets by 36.1%, 20.5%, 32.2%, 37.7%, and 68.4%, respectively. The changes in lipid nutritional quality indexes, b* value and sensory quality of cooked fish fillets treated with WGO nanoemulsions were found to be more stable. The oil quality of the cooked fish fillets treated with WGO nanoemulsions was successfully protected because of WGO loaded nanoemulsions provided a larger contact area on the surface of the fish fillets.

Chemical composition, functional, powder, and sensory properties of tarhana enriched with wheat germ

In this study, the effect of supplementing wheat germ in the formulation of tarhana, a fermented Turkish soup, was investigated to determine the physicochemical, functional, powder, and sensory properties. For this purpose, wheat germ was added to the tarhana formulation using five different replacement ratios (100 + 0, 90 + 10, 80 + 20, 70 + 30, and 50 + 50% weight wheat flour + weight wheat germ). The replacement of wheat flour with wheat germ resulted in the following: a higher moisture content, a*, browning (BI) and yellowness (YI) indexes, total color change (ΔE*), pH, ash, protein, cellulose, fat, and total phenolic contents, and foaming capacity values and lower Hue angle, chroma, L*, starch content, water hydration and oil holding capacities, wettability time, hygroscopicity, and the Carr index and Hausner ratio values (p < 0.05). The changes in the BI, YI, ΔE*, protein, cellulose, and starch contents, water hydration, and oil holding capacities, and foaming capacity values were found to be linear depending on the replacement percentage. Results of the chemical analysis of the tarhana samples revealed that the ash, protein, and cellulose contents of tarhana can be significantly increased depending on the replacement percentage (p < 0.05). A highly acceptable tarhana sample, selected by the panelists, that closely resembled the control was produced from a 90% wheat flour + 10% wheat germ mixture.

Does intake of bread supplemented with wheat germ have a preventive role on cardiovascular disease risk markers in healthy volunteers? A randomised, controlled, crossover trial

OBJECTIVE

Intake of whole grains is associated with a reduced risk of cardiovascular disease (CVD). This evidence is also strong for bran alone, but findings about germ are conflicting. Our aim was to elucidate the role of germ in primary prevention of cardiovascular events, and therefore, a staple food was selected for 6 g of germ supplementation. This corresponds to sixfold increase in the global mean consumption of germ, while preserving the sensory proprieties of refined bread which is crucial for consumer's acceptance.

DESIGN

Randomised, double-blinded, crossover, controlled clinical trial with 15-week follow-up comprising a 2-week run-in, two intervention periods of 4 weeks each and a 5-week washout period.

SETTING

A single centre in the north of Portugal.

PARTICIPANTS

55 eligible healthy adults (mean age of 34 years and body mass index between 19 and 38 kg/m²) were randomly assigned.

INTERVENTIONS

The study consisted of two intervention periods including daily intake of refined wheat bread enriched with 6 g of wheat germ and control (non-enriched bread).

OUTCOMES

Changes in fasting cholesterol and triglycerides, fasting and postprandial glucose, insulin sensitivity and C reactive protein.

RESULTS

We observed no significant effect of daily intake of wheat germ on cholesterol and triglycerides levels, on postprandial glucose response and on insulin sensitivity. Incremental area under curve glucose and homeostasis model assessment for insulin resistance did not change, suggesting that 6 g of wheat germ have no effect on glucose metabolism. No effect was also observed in the subgroup of participants who complied with the protocol (n=47).

CONCLUSIONS

The absence of alterations on lipid and glucose profiles suggests that germ up to 6 g/day may have no preventive effect on CVD risk. However, it is important to investigate other food vehicles that can accommodate higher doses of wheat germ in future studies.

TRIAL REGISTRATION NUMBER

NCT02405507.

Effect of wheat and corn germs addition on the physical properties and crackers sensory quality

Crackers are a potential material for the addition of cereal germs as a functional ingredient because they are a popular bakery item. The suitability of cereal germs for crackers production was investigated in this study. The effect of cereal germs incorporation to wheat dough (at level 5, 10 and 15%) on the physical properties (specific volume, volume index, width, thickness and spread ratio) and sensory parameters (appearance, firmness, taste, odor and overall acceptability) of cracker were evaluated. It was shown that wheat and corn germ addition to crackers resulted in decreased specific volume from 1.65 cm3.g-1 (control sample) to 1.52 cm3.g-1 (10% corn germs addition) and volume index 3.20 cm (control sample) to 2.57 cm (15% wheat germ), whereas spread ratio increased from 4.71 (fine wheat flour) to 5.06 (15% corn germ). No significant differences were found between the values obtained for width and thickness for crackers supplemented with 5% wheat germ to control sample. Addition of corn germ and wheat germ at level 15% caused decrease volume index of crackers about 13 and 20%. On the other hand enriched crackers of wheat germ and corn germ at level 15% was increment spread ratio by 5 and 7%. Regarding to sensory properties the overall appearance was affected significantly by addition of wheat and corn germ. Higher addition of wheat and corn germ in the crackers adversely affected firmness, taste and odor of final products. In generally, sensory properties of crackers were markedly affected with addition of cereal germs. The most significant differences were observed in appearance of crackers, when the 15% of wheat or corn germs were added (15 and 30% decreasing of this attribute in compare to control sample, respectively). The results of sensory analysis also showed that the crackers incorporated with wheat germs up to 10% level resulted in products with good acceptability.