苹果酒香味成分与感官质量研究

采用相关分析、主成分分析对苹果酒的主要成分与感官质量的关系进行了研究。结果表明,苹果酒质量属性之间呈极显著正相关。酚类、酯类是影响苹果酒质量的主要风味物质。优质苹果酒的酚类、酯类指标是:咖啡酸含量大于12·5mg/L,香豆酸0·5~2·0mg/L,总酚含量在600~800mg/L之间;丁酸乙酯0·3~1·4mg/L,乳酸乙酯100~900mg/L,9-癸烯酸乙酯0·1~1·1mg/L,总酯30~500mg/L。     

浓缩苹果汁中农药残留去除方法的研究现状及展望

农药残留是影响我国苹果浓缩汁质量的关键问题。文中综述了我国浓缩苹果汁中的农药残留状况,指出浓缩苹果汁中常见的农药残留是有机磷杀虫剂,通过对浓缩苹果汁中农药残留方法研究进展的追踪,包括物理方法、化学方法以及微生物方法,对未来该领域的发展进行了展望。     

Surface modification of Co3O4 nanostructures using wide range of natural compounds from rotten apple juice for the efficient oxygen evolution reaction

In this study, a new strategy has been produced to use a rotten apple juice as a source for the surface modification of Co₃O₄ nanostructures, giving rise to efficient electro-catalysts for driving oxygen evolution reaction (OER) at relatively low over potential. We have studied the morphology, chemical composition, and crystalline aspects of Co₃O₄ nanostructures using different analytical techniques. The Co₃O₄ nanostructures grown with rotten apple juice were observed with low impurity of Fe and P, surface modification, reduced particle size, high concentration of oxygen vacancies, defects and cubic phase of Co₃O₄. Furthermore, we have used the surface modified Co₃O₄ nanostructures for water electrolysis and noticed the significant performance towards OER in alkaline conditions. The electrochemical characterization revealed that the Co₃O₄ nanostructure prepared with 20 mL of rotten apple juice exhibits an overpotential value of 269 mV at 20 mA/cm² current density. The charge transport resistance (Rct) at the interface was estimated around 118.9 Ω, confirming an excellent reaction kinetics on the Co₃O₄ nanostructures and highly supported efficient performance towards OER. The Co₃O₄ nanostructures prepared with 20 mL of rotten apple juice has shown an acceptable durability for 40 h, verifying the long-term use. The performance of Co₃O₄ nanostructures with apple juice could be attributed to high oxygen vacancies due to high density of Co²⁺ ions on the surface, impurities of Fe and P, reduced nanoparticle size, defects in the structures, and favorable chemical composition. At the end, surface modified Co₃O₄ nanostructures was observed as an outperformed electrocatalyst when prepared with rotten apple juice. Therefore, this can be used in diverse purposes including energy conversion and storage applications.     

虫螨克防治梨木虱,苹果黄蚜,山楂叶螨的效果

２５％虫螨克乳油是一种广谱性杀虫杀螨剂，具有触杀和胃毒作用，且有一定的杀卵活性。经１９９３￣１９９４年试验证明，虫螨克对梨木虱防效显著，能有效地控制苹果黄蚜和山楂叶螨等虫螨的为害。     

Extraction of Golden Delicious apple puree: Experimental comparison of three different methods

In this paper, three different processes for puree extraction from Golden Delicious apples and enzyme inactivation are analyzed and compared: (i) hot extraction technique, (ii) cold extraction technique and (iii) a newly developed vacuum puree extraction technology (Zenith Chrono®). The analysis was carried out by means of manual laboratory operations reproducing the three processes. The primary objective of this study was the evaluation of the minimum amount of ascorbic acid that must be added to the three fruit purees in order to contain oxidization and color change in the products. Afterwards, the residual enzymatic activity was checked and characteristics of the products were compared (i.e. fraction of dried solids and consistency of the puree). All of the processes achieved complete enzyme deactivation and an imperceptible color change, and the results of this paper support interest in vacuum puree extraction technology.     

Viscoelasticity, texture and ultrastructure of cut apple as affected by sequential anti-browning and ultraviolet-C light treatments

The aim of this work was to analyze the effect of UV-C radiation (fluence: 11.2 kJ/m²), with or without an anti-browning pretreatment containing 1% (w/v) ascorbic acid plus 0.1% (w/v) calcium chloride, on the linear viscoelastic properties (oscillatory shear and creep/recovery), instrumental texture (TPA), sensory texture and ultrastructure (ESEM, TEM) of cut apple. Changes in structural features and viscoelastic parameters were mainly evidenced after refrigerated storage. All samples showed a viscoelastic solid behavior with the storage modulus (G′) dominating the viscoelastic response. Overall, both dynamic moduli decreased, and instantaneous compliance (J₀), decay compliances (J₁ and J₂) and fluidity significantly increased after treatments and storage at 5 °C, while retardation times were in general constant. Fracture properties proved to be the most highly correlated with sensory texture. The test panel only significantly differentiated stored untreated apple from the other samples regarding fracturability and juiciness. Mechanical spectra and creep parameters showed ability to evidence ultrastructural differences (rupture of membranes, swelling of cells, alteration of cell walls) in the surface of cut apples subjected to the different treatments.     

Preliminary studies on microbial polysaccharides from different Penicillium species as flavour stabiliser in cloudy apple juice

This research deals with the production of water‐soluble polysaccharides from six polysaccharide‐producing Penicillium species. Eup. pinetorum ATCC 14770 was promising for exo‐ and endopolysaccharides production under various cultural conditions. pH 5.0, 7 days, and pH 8.0, 10 days, were the optimum for the production of exo‐ and endopolysaccharides, respectively, at 30 °C in medium containing glucose and peptone. HPLC results revealed that both polysaccharides were composed of pectin, cellulose and hemicellulose. Exopolysaccharides produced by Eup. pinetorum was subjected to evaluation as a natural flavour stabiliser in cloudy apple juice (CAJ). Twenty‐one volatile compounds classified into esters, aldehydes, alcohols and ketone were detected, only eighteen compounds of which were characterised by their odours threshold. The esters and alcohols are accounting for 87.64% and 5.44% of total volatiles, respectively. This study indicates that the use of exopolysaccharides as an alternative flavour stabiliser in CAJ is very promising.     

INFLUENCE OF APPLE JUICE TREATMENTS ON THE CIDER MAKING PROCESS

This study was conducted to examine the influence of the following apple juice treatments on different parameters of cidermaking process: sulphiting (50 mg/L of total S0₂), clarification with pectolytic enzymes (Ultrazym 100 G, 3g/hL), and bentonite fining (lOOg/hL). The different treatments slowed down alcoholic fermentation, the greatest effect being found for the combination of the three treatments. With respect to malolactic fermentation, must sulphiting, with or without the other two treatments, delayed this process, which took place after alcoholic fermentation. The low levels of lactic acid bacteria during this period can explain this delay. The only treatment that had any significant influence on volatile acidity was sulphiting, either on its own or in combination with the other treatments. Thus lower acetic acid levels were detected in ciders treated with SO₂ .     

Representativeness of Apple Aroma Extract Obtained by Vacuum Hydrodistillation: Comparison of Two Concentration Techniques

ABSTRACT: Vacuum hydrodistillation, which is a very gentle work-up procedure, has never been used for the extraction of apple aroma. During the concentration of aroma that follows vacuum hydrodistillation, some very volatile components can be lost. The aim of this study was to compare 2 different concentration techniques, liquid-liquid extraction and solid phase extraction, to obtain an apple aroma extract as close as possible to fresh apple. After the elimination of solvent from the extract by gas chromatography, the study of the odor characteristics of solvent-free extracts was made possible. Vacuum hydrodistillation was convenient for fresh apples.