Improving the Flavour of Enzymatically Hydrolysed Beef Liquid by Sonication.

Beef potentiator is an important flavour enhancer in the food industry, while it is prone to generating insufficient compounds with umami and sweet tastes and compounds with a fishy odour during enzymatic hydrolysis of beef, resulting in poor flavour of beef potentiator. It has been extensively reported that sonication is capable of improving food flavour. However, the effect of sonication on the flavour of enzymatically hydrolysed beef liquid (EHBL) was scarcely reported. Herein, we investigated the effect of sonication on the flavour of EHBL using quantitative descriptive analysis (QDA), physicochemical analysis and SPME-GC-olfactometry/MS. QDA showed that sonication had a significant effect on taste improvement and off-odour removal of EHBL. Compared with the control, sonication (40 kHz, 80 W/L) increased the contents of total nitrogen, formaldehyde nitrogen, total sugars, reducing sugars, free amino acids (FAAs) and hydrolysis degree of EHBL by 19.25%, 19.80%, 11.83%, 9.52%, 14.37% and 20.45%. Notably, sonication markedly enhanced the contents of sweet FAAs, umami FAAs and bitter FAAs of EHBL by 19.66%, 14.04% and 9.18%, respectively, which contributed to the taste improvement of EHBL. SPME-GC-olfactometry/MS analysis showed that aldehydes and alcohols were the main contributors to aroma compounds of EHBL, and sonication significantly increased the contents of key aroma compounds and alcohols (115.88%) in EHBL. Notably, sonication decreased the contents of fishy odorants, hexanoic acid and nonanal markedly by 35.29% and 26.03%, which was responsible for the aroma improvement of EHBL. Therefore, sonication could become a new potential tool to improve the flavour of EHBL.

The latest advances on soy sauce research in the past decade: Emphasis on the advances in China.

As an indispensable soybean-fermented condiment, soy sauce is extensively utilized in catering, daily cooking and food industry in East Asia and Southeast Asia and is becoming popular in the whole world. In the past decade, researchers began to pay great importance to the scientific research of soy sauce, which remarkably promoted the advances on fermentation strains, quality, safety, function and other aspects of soy sauce. Of them, the screening and reconstruction of Aspergillus oryzae with high-yield of salt and acid-tolerant proteases, mechanism of soy sauce flavor formation, improvement of soy sauce quality through the combination of novel physical processing technique and microbial/enzyme, separation and identification of soy sauce functional components are attracting more attention of researchers, and related achievements have been reported continually. Meanwhile, we pointed out the drawbacks of the above research and the future research directions based on published literature and our knowledge. We believe that this review can provide an insightful reference for international related researchers to understand the advances on soy sauce research.

Efficient degradation of soybean protein B3 subunit in soy sauce by ultrasound-assisted prolyl endopeptidase and its primary mechanism.

Prolyl endopeptidase can partially degrade soybean protein B3 subunit and alleviate soy sauce secondary precipitate. In this study, the influences of ultrasound-assisted prolyl endopeptidase on the degradation of soybean protein B3 subunit of soy sauce and primary mechanism were investigated using SDS-PAGE, MALDI-TOF-MS, circular dichromatic spectrometer, fluorescence spectra, etc. Results showed that ultrasound-assisted prolyl endopeptidase enhanced 72% degradation rate of B3 subunit and reduced soy sauce secondary precipitate remarkably, meanwhile significantly increased content of organic taste compounds of soy sauce compared with control (p < 0.05). Sonication markedly reduced percentage of α-helix and increased percentage of random coil, made hydrophobic amino acids inside prolyl endopeptidase exposed to its surface and enhanced its flexibility, which facilitated the binding of prolyl endopeptidase active center with B3 subunit and finally enhanced the latter's degradation rate and appearance quality of soy sauce. This work laid a foundation for solving soy sauce secondary precipitate.

Research Advances in Preparation, Stability, Application, and Possible Risks of Nanoselenium: Focus on Food and Food-Related Fields.

Nanoselenium is a promising selenium supplement as a result of its low toxicity and high bioavailability. However, the understanding on the preparation, stability, bioavailability, possible risks, and related underlying mechanisms of nanoselenium is not in-depth. Thus, the above aspects were reviewed on the basis of the latest literature. The reducing capacity and stability of the reducing agent and binding force between nanoselenium and the template decide the nanoselenium stability. Although research on nanoselenium application in food, agriculture, livestock, and aquaculture has been widely carried out, it is not widely applied in the fields. Se-containing amino acids are synthesized using nanoselenium adsorbed by organisms, and they constitute Se-containing proteins with other amino acids, which improves the health of organisms via scavenging excessive radicals. Notably, excessive nanoselenium intake generates redundant Se-containing amino acids, leading to dysfunction of key proteins in organisms, and its toxic doses vary with organisms. Furthermore, some issues related to nanoselenium still need to be solved urgently.

Ougan juice debittering using ultrasound-aided enzymatic hydrolysis: Impacts on aroma and taste.

The optimal sonication conditions (40 kHz, 80 W/L and 60 min) during Ougan juice debittering by Aspergillus niger koji extract were established. Enzymatic hydrolysis degrees of naringin and limonin were enhanced to 89.90% and 36.16%, and enzymatic hydrolysis time was shortened by 33%. Sonication significantly enhanced activities of α-l-rhamnosidases, ß-glucosidases and limoninases from A. niger koji extract and facilitated break of CO bonds in naringin (p < 0.05). These accounted for the enhanced enzymatic hydrolysis degrees and velocities of bitter compounds. Meanwhile, sonication lowered 40%, 7% and 21%, 13%, 11%, 25% of bitter, sour tastes and green, citrus-like, floral, woody notes, but enhanced 18% and 15% of fruity and sweet notes, resulting in 38% and 33% increases in over-all taste and aroma scores. Lowered levels of bitter compounds, organic acids, green, citrus-like, floral, woody aroma compounds and enhanced levels of fruity, sweet aroma compounds caused by sonication accounted for the flavor improvements.