In this study, a novel method to clarify bayberry juice with composite clarifiers, chitosan and sodium alginate, has been designed. The optimal conditions were as follows: using chitosan 0.05 g/L first and then sodium alginate 0.05 g/L as composite clarifiers, standing for 2 h at 25 °C. The transmittance increased from 0.08 to 91.2% after treating by composite clarifiers, which was significantly higher than using chitosan (44.29%) and sodium alginate (38.46%) alone. It was also found that sedimentation time of juice treated by composite clarifiers was about 60% shorter than using single clarifiers. Meanwhile, the reduction of anthocyanin in juice was 9.16% for composite clarifiers treatment, being less than that for the single sodium alginate and previous related researches. In addition, the color and aroma of bayberry juice treated by composite clarifiers were improved. Juice treated by composite clarifiers had the highestL* value with 52.48 and looked more attractive. The present research revealed that content of beta-damascenone and dihydro-5-pentyl-2(3H)-furanone increased after treatment with composite clarifiers which contributed more to the pleasant aroma. Overall, the developed method improved the clarification effect and sensory quality, and reduced the sedimentation time, which may be promising in the production of clear bayberry juice.Keywords:bayberry juice;clarification;chitosan/sodium alginate;composite clarifiers;aroma
Bayberry juice is favored for its unique taste and flavor, while heat sterilization tends to reduce the aroma quality during processing, which limits its acceptability to consumers. To address this issue, we use exogenous polyphenols to regulate flavor compounds to improve the product quality. Total 13 differential key aroma-active compounds were identified between fresh bayberry juice (FBJ) and heat-sterilized bayberry juice (HBJ) using aroma extract dilution analysis (AEDA), orthogonal partial least squares-discriminant analysis (OPLS-DA) and odor activity values (OAVs). Further, eight polyphenols were added to investigate their influences on the aroma quality of HBJ respectively. The results showed that all tested polyphenols could maintain the aroma profile of HBJ closer to FBJ and improve the odor preference of HBJ, among which resveratrol and daidzein were most effective. Their aroma molecular regulatory mechanism involved enhancing the characteristic aroma of bayberry and reducing the certain off-flavored compounds produced by heat sterilization.
Xueying Gao,Jie Shang,Minghao Zhang,Hao Yan,Kai Yang,Yan Wang
Bayberry lacks a fruit skin covering and is prone to microbial contamination after harvest. Related products, such as Bayberry juice, can also be affected. Cold plasma (CP) shows promising antimicrobial applications in fruit juice, but its antimicrobial efficacy and underlying mechanisms against yeast remain inadequately explored. Therefore, this study aimed to elucidate the antimicrobial activity of CP against Kazachstania bulderi in bayberry juice, investigate its mechanisms through transcriptomic analysis. Results revealed that CP exhibited excellent antibacterial efficacy. Flow cytometry and transmission electron microscopy showed that CP caused wrinkling of yeast cell membranes and walls, mechanical damage to organelles and leakage of cellular contents. Transcriptomic sequencing identified a total of 1200 differentially expressed genes, primarily involved in amino acid synthesis, ribosome function, DNA repair, cell membrane and cell wall biosynthesis, and central carbon metabolism pathways. These changes indicated that CP induced cell membrane rupture and content efflux, leading to disruption of intracellular metabolic homeostasis, and that these damages induced the yeast itself to respond to CP stress through a series of stress responses such as the synthesis of amino acids and proteins and DNA repair. Regarding potential effects on juice nutrition and flavor, experimental results indicated that treatment had no significant impact on total phenols, total soluble solids, ascorbic acid, polyphenol oxidase, reducing sugars, total acidity, color, and key aroma components of bayberry juice. Additionally, CP alleviated the decline in total antioxidant capacity and total phenol content during juice storage, as well as the degradation of anthocyanins. This study suggests that cold plasma may be a promising method for juice sterilization and provides new insights into the inactivate mechanisms of cold plasma on yeast.
危险品化学品经营许可证（带存储）