Search

[Objectives] To explore the effects of different sterilization conditions on nutrition and flavor of apple vinegar. [Methods] Five kinds of high temperature short time (HTST) sterilization conditions were selected to treat apple vinegar, and the volatile aroma components and the content of active components in apple vinegar before and after sterilization were analyzed. [Results] Compared with the control, the contents of total acid and malic acid in the samples after sterilization changed little, but the contents of citric acid increased significantly ( P < 0. 01), and the contents of total phenols, ascorbic acid and total flavonoids decreased. Ethyl acetate, isopentyl acetate, ethyl caprylate, phenethyl acetate, 1-pentanol, phenylethyl alcohol, acetic acid, and sec-butyl ether were the characteristic aroma components which contributed to the flavor of apple vinegar. As sterilization temperature increased, the content of esters decreased, while the content of acids, alcohols and aldehydes increased. The contents of nutrition, active components and volatile aroma components in apple vinegar under 100 °C and 30 s sterilization conditions had little change compared with other sterilization conditions, so 100 °C and 30 s were the optimal sterilization conditions. [Conclusions] Under different sterilization conditions, the content of flavor components in apple vinegar will change greatly, which will affect the quality of apple vinegar. [ABSTRACT FROM AUTHOR]

[Objectives] The paper was to study the effect of magnetic field technology on physicochemical properties of fresh-cut apple during storage. [Methods] Using fresh-cut apples as materials, magnetic field assisted refrigeration and conventional refrigeration control groups were set up, and the preservation effects of magnetic field assisted refrigeration on fresh-cut apples were tested by measuring the changes of microorganisms and physicochemical indicators. In this experiment, the conditions of magnetic field assisted refrigeration group was set as follows: temperature 4 °C, magnetic field intensity 5 mT, static magnetic field, and storage for 6 d. [Results] At 6 d post storage, the weight loss rate, total number of colonies and total number of fungi of fresh-cut apples increased; the i" value and hardness showed a downward trend; the soluble solid content first increased and then decreased; and the total acid decreased first and then increased. The above indicators in magnetic field assisted refrigeration group changed more gently than that in conventional refrigeration group. Compared with conventional assisted refrigeration, the weight loss rate of fresh-cut apples treated by magnetic field combined with 4 9C refrigeration was reduced by 68.00%; the hardness was increased by 12.23%; the total number of colonies and total number of fungi were reduced by 64.15% and 37.50%; and the L" value did not change much. High content of soluble solids and total acid was maintained. [Conclusions] Magnetic field assisted refrigeration delays quality deterioration of fresh-cut apples during storage, prolongs shelflife, and further improves their edible quality and commodity value. [ABSTRACT FROM AUTHOR]

Due to its unique advantages, molecular marker technology is widely applied in the research of forest tree species. This paper reviewed the application of molecular marker technology in tree species resource diversity, germplasm identification, genetic map construction, gene mapping and marker-assisted selection (MAS) breeding. In addition, it elaborated the great significance of molecular marker technology to promote the sustainable development of forestry production in China. [ABSTRACT FROM AUTHOR]

[Objectives] To screen functional probiotics for apple fermentation and study their probiotic properties. [Methods] A total of 35 strains were screened from traditional fermented foods in different regions. After primary screening, re-screening and research on growth characteristics, two characteristic strains, CTCF-LCl (LC1, with strong acid production ability) and CTCF-LTl (LTl, with strong adaptability), were obtained. [ Results] The results of physiological and biochemical identification and 16S DNA-based identification show that LCl is Lactobacillus casei and LTl is Lactobaicillus reuteri. Their fermentation performance in apple juice was tested, and it was found that the two strains grew well in the fermentation broth, and the total number of colonies could reach IO9 cfu/mL. The final pH value of LCl fermentation broth dropped below 3.5, and the total acid content exceeded 12 g/L. The pH of LTl fermentation broth dropped to 3.9, and the total acid content also exceeded 6 g/L. In the study on the antioxidation property of apple juice, it was found that after high temperature and high pressure steam sterilization, the DPPH free radical scavenging rate of apple juice extract increased by 35.8%, and potassium ferricyanide reduction capability increased by 68%. After fermentation by LCl and LTl, the potassium ferricyanide reducing power of apple juice was increased by 42. 9%. [ Conclusions] This has a good application prospect in the development of fruit and vegetable juice fermented beverages. [ABSTRACT FROM AUTHOR]

This paper studied the fermentation rules of apple cider vinegar from fruit juice, to provide a theoretical guidance for the production of apple cider vinegar. Using Fuji apples as raw materials, the process parameters (fermentation temperatnre, fermentation time, stirring speed, and inoculat ion amount) of apple cider vinegar fermentation were optimized through single-factor experiments and response surface analysis. The results indicated that the fermentation temperatnre had no significant effect on the total acid content of apple cider vinegar fermentation, the fermentation time had an extremely significant effect on the total acid content of apple cider vinegar fermentation, and the stirring speed and inoculation amount had a significant effect on the total acid content of apple cider vinegar fermentation. Through process optimization, the optimal process parameters for apple cider vinegar fermentation are fermentation temperature of 33 °C, fermentation time of 39 h, stirring speed of 1500 r/min, and acetic acid bacteria inoculation amount of 7%. Under such conditions, the total acid content of fermented apple cider vinegar is 62. 22 g/L, very close to the predicted value of the model, indicating that the process parameters of acetic acid fermentation obtained by response surface methodology ( RSM) optimization are reliable and can be used for actual production prediction. [ABSTRACT FROM AUTHOR]

Using jujube juice prepared from red jujube as raw material and Saccharomyces cerevisiae as experimental strain, the effect of nutrients on the content of total ester in jujube wine was studied. The nutrients affecting the total ester content of jujube wine were glutamine, arginine, calcium chloride and biotin by Plackett-Burman design. Through the steepest ascent test, it was determined that the central points of the optimum addition of nutrients were glutamine 40 mg/L, arginine 50 mg/L, calcium chloride 35 mg/L and biotin 0. 25 mg/L, respectively.Through Box-Behnken experiment design, taking glutamine, arginine, calcium chloride and biotin as experimental factors, and the content of total ester in jujube wine as response value, the response surface optimization experiment was carried out and the verification experiment was also carried out. It was found that the response surface model can be used to predict the total ester content of jujube wine when nutritional elements were added. When the content of total ester in jujube wine was the highest, the optimal combination of nutrients was glutamine38. 8 mg/L, arginine 53. 8 mg/L, calcium chloride 35. 7 mg/L and biotin 0. 3 mg/L. At this point, the content of total ester in jujube wine was 628 mg/L, which was very close to the predicted value. Through the sensory evaluation of jujube wine, it was found that adding nutrients could help to improve the taste of jujube wine, and the fermentation method of jujube wine by adding nutrients was simple and feasible. [ABSTRACT FROM AUTHOR]

Carrot juice was fermented by probiotic Lactobacillus casei (CTCF-LC1) and Lactobacillus reuteri (CTCF-LT1) with sensory score as the main evaluation index, and the fermentation process was optimized by single factor and response surface experiments. The optimum ratio of fermentative strains CTCF-LC1 • CTCF-LT1 was FI, fermentation time was 8 h, inoculum size was 3. 1% and fermentation temperature was 26.6° C. Under the optimum conditions, the sensory score of fermented carrot juice was 91.3, pH was 4. 50, total acid content was 3. 73 g/L, total sugar content was 54.25 g/L, and reducing sugar content was 28.41 g/L. The carrot juice has bright orange color and stable slate. It not only has the fresh flavor of fruit and vegetable juice, but also has the unique aroma from lactic acid bacteria fermentation, as well as soft and even taste, moderate acidity and sweetness. The changes of aroma components of carrot juice before and after fermentation were analyzed by headspace solid phase microextraction (HSPME) coupled with gas chromatography-mass spectrometry (GC-MS). After fermentation, substances with medicinal flavor components were reduced, and a lot of floral and fruit-scented substances were produced, such as methyl myris-late, β-pinene, phenylethanol, and geraniol. Therefore, the results of this study can provide a theoretical basis for the development of fermented (mil and vegetable juice products with unique flavor substances. [ABSTRACT FROM AUTHOR]