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A commercial yeast strain (L) and five yeast strains (Y-1, Y-2, Y-3, Y-4 and Y-5) isolated from different specialty sourdoughs were checked for their ability to metabolize sugars and organic acids and their effects on volatile flavor substances and sensory quality of sourdough and bread. The results showed that yeast Y-1, Y-3, Y-4 and Y-5 all showed good sugar metabolism ability and were able to produce high yields of malic acid, lactic acid and succinic acid. In terms of sensory quality, the sourdough fermented by each of the five yeast strains had good flavor; sourdoughs Y-3 and Y-4 had better sensory characteristics than other samples. It was found that the hardness of bread made with sourdough Y-3 was reduced by 16.77% and adhesiveness by 72.39% in comparison to commercial yeast L. The sensory score for fermented flavor of bread Y-3 was the highest, 7.74 points, indicating that yeast Y-3 could obviously improve the texture and flavor of bread. The results of headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) showed that the relative contents of alcohols in sourdoughs and breads made with L, Y-3 or Y-4 were the highest, ranging from 72% to 81%. Also, esters were the main flavor substances in sourdough, while aldehydes were predominant in bread. Moreover, the principal component analysis (PCA) of volatiles showed good discrimination among the three sourdoughs as well the three breads; ethyl hexanoate and ethyl caprylate contributed significantly to the flavor of sourdough Y-3, while hexanal and trans-2-nonenal were the key flavor components of bread Y-3. These substances provided rich aromas to sourdough and bread. In conclusion, yeast Y-3 plays a positive role in improving the taste quality of bread.

Color is an important factor affecting the sensory quality of fruit and vegetable (FV) products. The vibrant and stable color of FV products can give people a good visual enjoyment, which can in turn promote consumers’ appetite and increase the market value of the products. This paper summarizes the types and properties of natural colorants in FV, clarifies the effects of thermal and non-thermal drying technologies and their combination on the color of FV products, reveals the influence mechanism of colorant degradation products on the products’ quality, and reviews the color preservation technologies of dried FV. We hope that this review could provide a theoretical basis for the color preservation and quality enhancement of dried FV products.

The topological antiferromagnet γ -FeMn is a fascinating material for studying unconventional magnetic properties and topological transport phenomena though high-quality γ -FeMn has been obtained on the Cu substrate for magnetic research. However, the difficulty of growing single-crystalline γ -FeMn films on insulating substrates has prevented experiments from exactly verifying many theoretical predictions on their transport properties. Ultrathin Cu buffer films have been considered for solving this problem but failed because the crystal quality and thickness of Cu films achieved in previous works do not satisfy the growth buffer criteria for γ -FeMn. In this work, the growth of 5-nm-thick Cu films on SrTiO 3 (001) substrates was studied. It was found that single-crystalline ultrathin Cu films with roughness as low as 1 nm are obtained on the insulating substrate. We subsequently obtained high crystalline quality γ -FeMn films with smooth surface and verified their antiferromagnetism. Finally, two aspects of the influence of Cu films on adjacent films have been analyzed. Our results facilitate the experimental exploration of the fascinating properties of γ -FeMn. [ABSTRACT FROM AUTHOR]