Ripening and Cold Storage Changes in the Quality Characteristics of Nonmelting Clingstone Peaches (FLA 9-20C)

Minolta “a” values, SS/TA ratio, sucrose, total sugar contents, and sweet sensory scores increased significantly with increased degree of maturity of unripened peaches. Firmness, Minolta “L” values, hue angle, TA, sorbitol, green and sour flavor attributes, and peach complex and fruity/ester aromas decreased significantly with maturity. Maturity 1 and 2 peaches stored for 8 wk at 0° C and subsequently ripened showed no significant change in physical characteristics except for firmness which increased at 8 wk storage. Maturity 1 and 2 peaches could be ripened at 20° C for up to 15 days and stored at 0° C for 8 wk without notable change in quality.     

桃醋液态发酵过程中主要成分及有机酸的变化

以成熟桃为原料,采用液态发酵法酿造原浆桃醋,对"两步法"酿造桃醋过程中主要成分的动态变化进行分析。桃打浆后接种0.05%的果酒酵母带皮渣酒精发酵,在20℃恒温发酵80 h,发酵液酒度为6.07%。醋酸发酵使用自吸式液态深层发酵罐,接种10%活化的醋酸菌菌种,发酵温度34℃,经60 h醋酸发酵,桃醋酸度为3.54%。桃醋发酵液中检出9种有机酸,包括草酸、甲酸、苹果酸、α-酮戊二酸、乳酸、醋酸、柠檬酸、富马酸和琥珀酸,9种有机酸在酒精发酵和醋酸发酵阶段均发生显著变化,对发酵液的酸度和品质产生显著影响。酒精发酵阶段,乳酸大量积累;苹果酸、柠檬酸被消耗显著降低。醋酸发酵阶段酒精大量转化醋酸,醋酸含量显著上升;而其它大部分,如乳酸、苹果酸等有机酸显著降低。试验确定的发酵方法适用于桃醋生产。     

Pectolytic Enzyme Activity During Intermittent Warming Storage of Peaches

Pectin enzyme evolution in peaches intermittently warmed at 15°C (15°C-IW) and at 20°C (20°C-IW) for 24 hr every 8 days of storage at 0°C, was followed. Cold storage increased PME activity until a constant level was reached, whereas PG decreased after 2 wk. 15°C-IW had a similar effect to conventional cold storage. 20°C-IW induced a different behavior, PG activity increasing and PME activity decreasing after 2 wk of storage. This different behavior seemed to be related to the development of chilling injury, since 15°C-IW did not alleviate chilling injury but 20°C-IW did. Chilling injury development during storage was associated with continuous PME activity and inhibition of endo-PG activity after the second week of storage, regardless of exo-PG activity.     

成熟温度对牦牛毛霉菌奶酪成熟过程中品质的影响

文章通过研究不同成熟温度对牦牛毛霉菌奶酪成熟过程的影响,找寻最适应的温度及成熟时间.选取实验材料牦牛毛霉菌奶酪,将其置于不同的成熟温度下(20,25,30℃),选取相应成熟时间节点,测定质构、色泽、蛋白质分解、pH值等.结果 表明,成熟温度为25℃时,牦牛毛霉菌奶酪在第6天时质构达到最佳值,此时感官评分也较高.3组牦牛...     

不同溶质型桃果实成熟软化过程中细胞壁多糖分子质量的分布变化

以软溶质型桃"雨花三号"和硬溶质型桃"加纳岩"果实为试材,采用高效液相色谱法测定细胞壁多糖组分分子质量分布变化。结果表明:CDTA、Na2CO3和KOH组分多糖的分子质量在两种桃果实成熟软化过程中都发生下降,说明细胞壁多糖在桃果实成熟过程中发生了解聚,高分子质量物质向低分子质量物质转变。但两种溶质型桃在多糖组分分子质量的大小、各分子质量组分含量及出现解聚的时间都明显不同,说明多糖组分的解聚方式对桃果实软化过程有一定影响。     

转录和蛋白质组学分析热空气处理对桃果实采后冷藏期间糖酸和酚类物质代谢的影响

桃果实采后低温贮藏易发生冷害,为研究热空气（hot air,HA）处理对桃果实冷藏过程中调控代谢途径的作用,本实验采用HA处理（40 ℃、4 h）桃果实,于（1±1）℃下贮藏35 d,每隔7 d取样并对可溶性糖、柠檬酸、苹果酸、总酚、总黄酮含量和花色苷含量等指标进行测定,同时选取样品进行转录组学和蛋白质组学分析。结果表明：HA处理可以有效抑制桃果实冷藏期间蔗糖、柠檬酸、苹果酸、总酚和总黄酮含量的下降,并抑制果糖和葡萄糖含量的上升,同时HA显著提高了桃果实花色苷的含量（P＜0.05）。转录组和蛋白质组学分析结果表明,HA处理调控的差异表达基因和蛋白主要集中于碳水化合物代谢和次级代谢物代谢途径;桃果实糖酸代谢变化主要与转化酶、蔗糖合酶、蔗糖磷酸合酶、苹果酸脱氢酶和柠檬酸合酶基因和蛋白的表达有关;HA通过上调苯丙氨酸解氨酶、香豆酸CoA连接酶、查耳酮合酶、二氢黄酮醇还原酶、花青素合成酶和类黄酮葡萄糖基转移酶的表达量,促进酚类、黄酮类和花青素的合成。综上所述,HA处理可以有效延缓桃果实采后糖酸和酚类物质含量的下降,并提高果实花色苷的含量。     

大久保桃的催熟条件研究

本文研究了冷藏后的大久保桃适宜的催熟方式、温度和时间对桃果实和软白桃罐头感官品质和理化指标的影响,并分析了原料利用率。结果表明：大久保桃采用打孔的PE袋包装,催熟效果较好,此时桃的腐败指数和褐变指数低,风味浓郁;有效冷藏18d内的大久保桃,30℃催熟3d后,生产的软白桃罐头感官和理化指标均达到国标要求;原料利用率均保持在83．31％以上。该研究为软白桃罐头加工中的桃催熟处理提供了技术依据。     

大久保桃的催熟条件研究

本文研究了冷藏后的大久保桃适宜的催熟方式、温度和时间对桃果实和软白桃罐头感官品质和理化指标的影响,并分析了原料利用率。结果表明:大久保桃采用打孔的PE袋包装,催熟效果较好,此时桃的腐败指数和褐变指数低,风味浓郁;有效冷藏18 d内的大久保桃,30℃催熟3 d后,生产的软白桃罐头感官和理化指标均达到国标要求;原料利用率均保持在83.31%以上。该研究为软白桃罐头加工中的桃催熟处理提供了技术依据。     

剁辣椒发酵过程中菌群与有机酸变化规律分析

以自然发酵为对照,以植物乳杆菌W-4进行剁辣椒纯种发酵。研究结果表明：在发酵过程中,接种发酵能使乳酸菌快速成为优势菌,较快地降低剁辣椒的pH值。接种发酵具有较高数量的菌落总数和乳酸菌,酵母菌在自然发酵和接种发酵中数量相当,变化趋势基本一致,而大肠菌群只在发酵前期出现,而后消失。有机酸测定结果表明接种发酵具有较高含量的乳酸,而自然发酵具有较高含量的柠檬酸和苹果酸,而乙酸只在自然发酵的前期出现。     

Pectin Changes in Ripening Cherry Fruit

Pectin solubilization was studied during ripening of cherry fruit. Pectic materials were isolated at specific stages during development. The proportion of alcohol-insoluble-material decreased on a fresh weight basis with ripeness, but increased per fruit. Pectic substances were divided into water-, oxalate- and acid-soluble fractions. The oxalate-and water-soluble part increased as acid-soluble components decreased. Water- and acid-soluble fractions contained many more neutral sugar residues than the oxalate-soluble fraction. Changes in individual sugars indicated the major alterations were the degradation of galactan and the absence of arabinan solubilization in acid-soluble pectic substance. Size exclusion chromatography showed absence of pectin depolymerization during ripening, indicating that fruit softening does not depend on pectin depolymerization.     

不同菌种大豆干酪后熟过程的研究

研究了3种不同大豆干酪后熟过程的变化情况。结果表明,L.rhamnosus+S.carnosus大豆干酪具有最低的pH和最高的酸度,同时具有最高的氨基氮含量和最高的活菌数。游离氨基酸分析表明,L.rhamnosus+S.carnosus大豆干酪中的游离氨基酸总量最高;L.rhamnosus大豆干酪降解产生的游离氨基酸以谷氨酸和精氨酸为主,S.carnosus大豆干酪和L.rhamnosus+S.carnosus大豆干酪降解产生的游离氨基酸则以色氨酸为主。脂肪酸分析表明,L.rhamnosus+S.carnosus大豆干酪C20以上的长链脂肪酸得到更加充分的降解。     

Color Kinetics During Ripening of Indian Mangoes

During ripening of mangoes, color change kinetics were studied with Alphonso, Banganapalli, and Neelam varieties. The internal and external color change was recorded using CIE-Lab color coordinates. L, a, b, and total color difference (ΔE) values were measured for internal pulp and external peel during the ripening period. Four kinetic models viz. zero order, first order, fractional conversion, and logistic models were used for modeling using MATLAB. Among the explored models, the logistic model was found to be more suitable to predict the changes in all external color coordinates in all the three varieties. Internal color coordinates of different varieties were exhibited contrasting behavior. So different kinetic models were proposed to predict the internal color change for different variety. The fractional conversion model was found to be not suitable in color change kinetics during ripening of mango.     

Flow Characterization of Peach Products During Extrusion

Suitability of Bingham, Herschel-Bulkley, Casson, and Mizrahi-Berk models, to characterize the flow behavior of peach products during extrusion was investigated. The Casson equation sufficiently described the flow of peach extrudates within the 49 to 125 s^-1 shear rate range. As concentration increased, yield stress and consistency coefficients increased. A rheological model was proposed to describe the viscosity of peach extrudates. The model incorporates the effect of shear rate by the Casson equation and the effect of concentration by a linear expression. The model provided good fit to the experimental data for peach extrudates reconstituted from drum-dried peach purees.     

Changes in Organic Acids During Malolactic Fermentation at Different Temperatures in Yeast-Fermented Apple Juice

Organic acids were analyzed during controlled malolactic fermentation conducted by a selected Leuconostoc oenos strain, performed at different temperatures (15 °C, 22 °C and 27 °C). The apple juice had been previously fermented by a Saccharomyces cerevisiae strain, at 15 °C and major organic acids were also monitored during this phase. The aim of this work was to study the effect of fermentation temperature on organic acid composition and on the main reactions that take place during malolactic fermentation, applicable to improving the cider making process at the industrial level.     

Changes of Phenolic Acids During Aging of Organic Wines

Grapes (Vitis vinifera L. origin var: Carignane, Cabernet Sauvignon, Merlot, Grenache, Columbard, and Semillon) were cultivated and processed according to accepted organic agriculture and organic wine techniques. Aged wines (5 years) were evaluated for changes of their phenolic acids. The highest reduction of gallic acid concentrations were determined in Cabernet Sauvignon (24.36 mg/L) and Carignane (16.00 mg/L) wines. The quantities of p-hydroxybenzoic acid decreased mostly in Carignane (22.47 mg/L) and Columbard (20.84 mg/L) wines. The decreases of syringic acid were dominant in Cabernet Sauvignon (2.34 mg/L) and Carignane (1.69 mg/L) wines. In the case of ferulic acid, the highest reduction was determined in Cabernet Sauvignon (3.97 mg/L) wines. The decreases of p-coumaric acid contents were the same and mostly in Merlot (1.06 mg/L) and Grenache (1.035 mg/L) wines. The principal component analyses results demonstrated the relations among aged wines produced from different grape varieties and their phenolic acids. The distribution of data was accumulated into two groups. The first group included total phenols, gallic acid, p-hydroxybenzoic acid, syringic acid, p-coumaric acid, and Merlot/Carignane/Grenache wines. The second one included ferulic acid and Cabernet Sauvignon wine.     

复合有机酸保鲜剂(OAA-7)在水蜜桃保鲜中的应用

研究了天然复合有机酸保鲜剂(OAA-7)在"浅间白桃"中的应用效果,发现300×10-6 OAA-7结合热处理(45±1℃,相对湿度为90%～95%)12h和冷藏(1.0±0.5℃)处理可以降低水蜜桃失重率,延缓还原糖和可溶性固形物含量的上升,对抑制腐烂、保持水蜜桃硬度、防止VC被氧化也有一定的帮助,显著提高水蜜桃的优果率.     

酸浆豆腐后熟过程中风味物质的形成途径分析

采集不同后熟阶段的酸浆豆腐为样本,对其游离氨基酸、有机酸、挥发性风味物质进行测定。结果显示,游离氨基酸和有机酸是滋味物质的主要来源,其中酸味氨基酸是主要的呈味物质,在不同的后熟阶段占总氨基酸的33%～35%。后熟过程中乳酸、乙酸和柠檬酸3 种有机酸是主要呈味物质且含量最高,其总量约占有机酸总量的50.08%～65.00%。后熟过程中共检测到84 种风味化合物,包括醛类、醇类、酚类、呋喃类等化合物,共同赋予酸浆豆腐独特的酵香风味。     

Sensory Changes During Ripening of Raw Ewes' Milk Cheese Manufactured With and Without the Addition of a Starter Culture

ABSTRACT: This study characterizes and compares the sensory aspects of raw ewes' milk cheeses manufactured with and without the addition of a starter culture using specifically developed sensory terminology. Furthermore, overall organoleptic quality was assessed at each ripening stage. Two different raw ovine milk cheese batches were manufactured with and without the addition of a freeze-dried starter. Sensory differences in odor, flavor, and texture were related to starter and raw milk flora activities during manufacturing and ripening. Cheeses made with the addition of a starter culture were scored higher by quality experts. Cheeses manufactured without a starter culture received higher scores for dirty and animal attributes, such as rennet, butyric, sharp, pungent, and brine, possibly related to lower quality scores. Conclusions reached in the present study coincide with previous ones; however, by using a sensory lexicon specifically developed for ewes' milk cheeses, it has been possible to describe slight and specific differences in the cheeses.     

桃罐头中腐败微生物的分离纯化及鉴定研究

通过对桃罐头中分离出的微生物进行分离培养、生理生化指标和反证试验进行鉴定和特性研究,初步断定其主要污染菌为凝结芽孢杆菌、黄色丝衣霉、蜡状芽孢杆菌等兼性厌氧菌,并依据实验数据绘制出了三种微生物的生长曲线,建立了一条检验桃罐头中微生物的技术路线。