In order to study the effect of osmotic solution characteristics on the texture of osmotic dehydrated yellow peach, changes in osmotic solution characteristics and the texture quality of ‘Baby Gold 8’ yellow peach slices were investigated during osmotic dehydration. After ultrasound or vacuum pretreatment, fresh-cut yellow peach slices were impregnated in a 30 °Brix sucrose, isomaltose, fructose or glucose solution (25 ℃) and sampled at time 0.5, 1, 2, 3, 4 and 5 h for analysis. The properties of osmotic solutions were evaluated in terms of total solid soluble (TSS) content, osmotic pressure, pH and turbidity. Results showed that the different initial osmotic solutions had the same total soluble solid (TSS) content; however, their turbidity, osmotic pressure, and pH were significantly different. At the initial stage of osmotic dehydration (0–2 h), a markedly decreasing trend in TSS content and osmotic pressure was observed, which could be accelerated by either pretreatment. At the late stage, both TSS content and osmotic pressure decreased slowly. The pH of osmotic solutions declined to a level close to that of fresh yellow peach fruit (4.30 ± 0.32) after 0.5 h, and then was not significantly change. As mass transfer occurred, the turbidity increased first rapidly and then slowly. Moreover, both hardness and chewiness fell significantly (P < 0.05). Correlation analysis indicated that the texture quality was positively correlated with osmotic pressure, TSS content and pH but negatively correlated with turbidity. Therefore, the texture of osmotic dehydrated yellow peach slices can be improved by controlling the characteristics of osmotic solution and adopting appropriate pretreatments.

Peaches are an ancient fruit in China, with great nutritional and commercial value. Peach fruit is a typical respiratory climacteric fruit, which is prone to browning within a short period of time after harvesting, and rapid browning and high browning degree occur during peach processing, which are difficult to control, affecting the quality and economic value of the fruit. At present, systematic research on the characteristics and mechanism of peach browning is lacking, as well as effective control techniques and methods. In this paper, the current status of research on the characteristics and mechanism of and the key factors for enzymatic browning in peach fruit is reviewed, and the techniques used for its control are summarized, aiming to provide a reference for the regulation of enzymatic browning during peach storage and processing and consequently to promote the quality improvement of fresh and processed peach products.

Berries have been one of the most popular fruits with the high nutritional value and processing prospects. A variety of berries with strong cold resistance are also produced in the northeast of China. These berries share the unique regional features, strong cold resistance, high nutritional value, and are rich in various active functions. A series of berry products have been formed in recent years. But it is limited to the acceptance of the initial processing of berry products, because of its their comprehensive quality, such as color, aroma, and taste under the low level of mechanization. Among them, the taste is one of the important indicators to evaluate the quality of fruit, which is closely related to the quality of processed products and the acceptance of consumers. In this study, ultra-high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS) and Gaschromatography-mass spectrometry (GC-MS) techniques were employed to investigate the taste features and composition of the four typical berries from cold regions, including Vaccinium uliginosum L., Lonicera cearulea L., Rubus idaeus L., and Ribes nigrum L.. The non-volatile and volatile substances of these berries were screened and then identified. Furthermore, electronic tongue analysis and sensory evaluation were conducted to obtain the overall fuzzy comprehensive scores of taste quality. Factor analysis was then performed. The results show that the alcohols, aldehydes, and hydrocarbons were the main volatile flavor substances in cranberry. There was the a high relative content of alcohols, acids, and esters in blackcurrant. The prominent relative content of ketones and acids in raspberry was induced the outstanding flavor features easy to distinguish. The volatile flavor substances of indigo fruit were mainly alcohols and esters, which were more balanced, compared with the rest berries. While there was no outstanding aroma. The findings revealed that Vaccinium uliginosum L. had a sugar-acid ratio of 4.41, and the characteristic volatile substances were α-terpinol and benzaldehyde, with the highest acid taste response from the electronic tongue. Ribes nigrum L. had a sugar-acid ratio of 3.80 and the characteristic volatile substances were phenylethanol and acetic acid, with the a relatively balanced taste response. Lonicera cearulea L. had a sugar-acid ratio of 3.37 and the highest total phenol content of (3.79±0.17) mg/g gallic acid equivalent content. Its characteristic volatile substances were n-hexene-alcohol and 3-hexene-1-alcohol, indicating the highest salt and umami taste response. Rubus idaeus L. had a sugar-to-acid ratio of 8.19 and the characteristic volatile substances were acetic acid and α-violone, with the highest sweet and bitter taste response. From the perspective of acceptability, the highest comprehensive score was found in Rubus idaeus L. While tThe comprehensive score was ranked in the descending order of the Lonicera cearulea L., Vaccinium uliginosum L., and Ribes nigrum L. The sensory evaluation correlation analysis showed that sour taste, fruit flavor, aftertaste, and aftertaste had a great influence on the berry selection. Screening, identification, and statistical analysis demonstrated that there were ten compounds of the non-volatile substances, including tagose, lactic acid, aloxalulose, oxalic acid, citric acid, aspartic acid, alizarin, 6α-mannobiose, sucrose, and isoquercetin. The overall fuzzy comprehensive scores of taste sensory decreased in the descending order of Rubus idaeus L., Lonicera cearulea L., Vaccinium uliginosum L., and Ribes nigrum L. The factor analysis indicated that the taste composition scores increased in the descending order of Ribes nigrum L., Lonicera cearulea L., Vaccinium uliginosum L., and Rubus idaeus L., indicating that the higher the score of flavor substance composition was, the lower the fuzzy comprehensive score was. These findings can provide a theoretical foundation to developfor developing the high-quality products using the four cold-region berries. At the same time, the taste regulation was considered to increase the added value of berry foods for better utilization in cold areas.

The taste of fruits is an important attribute of fruit quality. The taste substances in fruits stimulate the taste buds to produce taste sensations, which are transmitted through the gustatory nerves into the neural center, finally entering the cerebral cortex. The major taste substances in fruits are soluble sugars, organic acids, polyphenols, alkaloids, and other bitter substances. These taste substances altogether contribute to the unique taste of fruits. Taste regulation of fruit products such as canned fruits, dried fruit products, liquid fruit products, jams and preserved fruits has received increasing attention, and there are a growing number of studies on methods for the regulation of fruit product taste. Many methods including electronic tongue technology, molecular sensory science, and quantitative descriptive analysis have been applied for studying the taste of fruits. This article provides an overview of taste substances in fruits and fruit products and methods for their taste regulation, and introduces commonly used methods in fruit taste research, aiming to provide theoretical guidance for research in the field of fruit taste.

Recently, pectin has been used as an alternative for commercial prebiotic products to modulate gut microbiota. In this study, the standard diet (Chow group) and high fat diet containing 0% (HF group), 1%, 3%, 5%, 8% or 12% (m/m) apple pectin (HF-P group) were offered ad libitum for 8 weeks to 4-week C57BL/6J mice (n=10/group). Results showed that body weight gain (R²=–0.990), subcutaneous adipose accumulation (R²=–0.930), serum triglyceride elevation (R²=–0.879), acetate (R²=0.955) and propionate concentration reduction (R²=0.985) were suppressed by pectin from 1% to 12%, indicating dose response to pectin consumption. Moreover, abundance of obesity-related bacteria Coriobacteriaceae, and pectin-degradating bacteria, Faecalibaculum, Ruminococcus were significantly increased with pectin dosage increased, and the R² were 0.936, 0.963 and 0.937, respectively. Besides, attenuations for colonic injury and liver steatosis were observed after adding 5% and 8% pectin, respectively. This study confirmed the dose-sensitive manner of pectin to alleviate HF-induced obesity by modulating gut microbiota and enhancing short-chain fatty acids production.

To realize high-value utilization of discarded apple peel, this study investigated the effects of three selected commercial drying methods on drying kinetics, microstructure, color, phenolic stability and antioxidant capacity of apple peel. Apple peel was dehydrated by hot air drying (AD) at 75, 65 and 55 ℃, heat pump drying (HP) at 65, 55 and 45 ℃, and vacuum freeze-drying (FD), respectively. The results showed that HP was superior to AD and FD in terms of drying rate. In addition, HP at 65 ℃ provided high-quality dried apple peel due to less browning and brighter appearance, the highest retention of total phenolics (29.35 mg/g) and the strongest antioxidant activities, with the highest ABTS and FRAP value of 127.15 and 219.57 μmol TE/g, respectively. The content of the six major individual phenolics, i.e. caffeic acid, (-)-epicatechin, hyperoside, rutin, phlorizin and quercitrin, were found to be the highest in HP dried samples. Interestingly, the content of rutin was even increased after HP compared to the fresh sample. Considering drying efficiency, organoleptic quality and phenolic stability of the products, HP at 65 ℃ is suggested for drying of apple peel.