The potential of kiwifruit puree as a clean label ingredient to stabilize high pressure pasteurized cloudy apple juice during storage.

In the fruit juice industry, high pressure (HP) processing has become a commercial success. However, enzymatic browning, cloud loss, and flavor changes during storage remain challenges. The aim of this study is to combine kiwifruit puree and HP pasteurization (600 MPa/3 min) to stabilize cloudy apple juice during storage at 4 °C. A wide range of targeted and untargeted quality characteristics was evaluated using a multivariate approach. Due to high ascorbic acid content and high viscosity, kiwifruit puree allowed to prevent enzymatic browning and phase separation of an apple-kiwifruit mixed juice. Besides, no clear changes in organic acids, viscosity, and particle size distribution were detected in mixed juice during storage. Sucrose of apple and mixed juices decreased with glucose and fructose increasing during storage. The volatile changes of both juices behaved similar, mainly esters being degraded. Sensory evaluation demonstrated consumer preferred the aroma of mixed juice compared to apple juice.

Yi J ，Kebede B ，Kristiani K ，Buvé C ，Van Loey A ，Grauwet T ，Hendrickx M ... -  《-》

Minimizing quality changes of cloudy apple juice: The use of kiwifruit puree and high pressure homogenization.

Cloud loss, enzymatic browning, and flavor changes are important quality defects of cloudy fruit juices determining consumer acceptability. The development of clean label options to overcome such quality problems is currently of high interest. Therefore, this study investigated the effect of kiwifruit puree (clean label ingredient) and high pressure homogenization on quality changes of cloudy apple juice using a multivariate approach. The use of kiwifruit puree addition and high pressure homogenization resulted in a juice with improved uniformity and cloud stability by reducing particle size and increasing viscosity and yield stress (p < 0.01). Furthermore, kiwifruit puree addition reduced enzymatic browning (ΔE∗ < 3), due to the increased ascorbic acid and contributed to a more saturated and bright yellow color, a better taste balance, and a more fruity aroma of juice. This work demonstrates that clean label options to control quality degradation of cloudy fruit juice might offer new opportunities.

Yi J ，Kebede B ，Kristiani K ，Grauwet T ，Van Loey A ，Hendrickx M ... -  《-》

Effect of the apple cultivar on cloudy apple juice fermented by a mixture of Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus fermentum.

This study aimed to evaluate the fermentation performance of a mixture of Lactobacillus spp. in cloudy apple juices from nine cultivars. The results showed that cultivar influenced most the properties of the fermented cloudy apple juice. The fermented cloudy apple juices made from Changfu had the highest viable bacterial count and acetic acid contents (6.37 × 108 CFU/mL and 2.67 mg/mL, respectively). It also had higher sensory score, second only to Huaniu. The highest total sugar consumption, utilising fructose, glucose, and sucrose (33.07 mg/mL), was seen with Golden Delicious. Qinguan fermented cloudy apple juice had the highest contents of lactic acid (6.74 mg/mL) and total esters (921.36 μg/L); d-limonene also detected in this fermented cloudy apple juice. Of the nine cultivars examined in this study, Changfu, Qinguan, and Golden Delicious were the most suitable for producing fermented cloudy apple juice with better taste, higher viable count and more intense aroma.

Peng W ，Meng D ，Yue T ，Wang Z ，Gao Z ... -  《-》

Gas chromatography-mass spectrometry combined with multivariate data analysis as a tool for differentiating between processed orange juice samples on the basis of their volatile markers.

The contents of volatile aroma compounds in orange juice vary after high hydrostatic pressure (HHP) processing and pasteurization, and hence gas chromatography-mass spectrometry has potential for discriminating between orange juice samples according to the processing method. Effects of HHP processing and pasteurization on orange juice were investigated immediately after processing and after storage for 28 days at 4 °C. Processing decreased the contents of most terpenes and esters and increased those of alcohols and aldehydes. Volatile compounds that could serve as discriminant indicators of HHP processing and pasteurization were heptanal, (E)-2-heptenal, (E)-2-nonenal, and d-carvone and β-terpineol, p-mentha-1,5-dien-8-ol, carveol, and β-copaene, respectively. The discrimination abilities of pH, ascorbic acid, total soluble solids, and color were compared with those of volatile compounds, which were found to be lower. The compounds d-carvone and β-terpineol could be used as discriminant indicators of HHP-treated and pasteurized orange juice, respectively, throughout the storage period.

Bi S ，Sun S ，Lao F ，Liao X ，Wu J ... -  《-》

Anti-browning effect of Rosa roxburghii on apple juice and identification of polyphenol oxidase inhibitors.

Enzymatic browning control of cloudy fruit juice with natural substances has received much attention for improving its nutritional and commercial value. This study explored the anti-browning potential of Rosa roxburghii in apple juice. The anti-browning effects and mechanisms were evaluated by serial measurements of appearance, browning index, polyphenol oxidase (PPO) activity, UPLC-QE-Orbitrap-MS identification, inhibition kinetics and molecular docking. The results showed that Rosa roxburghii juice (0.25%-1.25% w/w) could effectively inhibit browning and PPO activity of apple juice. Ascorbic acid (1.67 g/100 g) as a reducing agent was a main anti-browning factor. Furthermore, seven phenolic compounds in Rosa roxburghii were screened as PPO inhibitors. Representative phenolic inhibitors induced mixed or competitive inhibition of PPO, mainly driven by hydrophobic forces and hydrogen bonds. This work demonstrates that Rosa roxburghii is a promising natural anti-browning ingredient to control the browning of cloudy apple juice due to abundant ascorbic acid and PPO inhibitors.

Yu K ，Zhou L ，Sun Y ，Zeng Z ，Chen H ，Liu J ，Zou L ，Liu W ... -  《-》