不同贮藏方式对鲜切大白菜食用品质的影响

为探究不同贮藏方式对于鲜切大白菜食用品质的影响,研究采用不同包装及贮藏温度对鲜切大白菜进行处理,通过测定其感官品质、抗坏血酸、可溶性蛋白质、可溶性固形物及亚硝酸盐含量的变化,探究不同贮藏方式对鲜切大白菜食用品质的影响。结果表明：两种冷藏（4±1℃）条件下（即冷藏与冷藏PE）鲜切白菜的感官品质均显著优于两种室温（18±2℃）条件（即室温与室温PE）（P≤0．05）,且两种冷藏条件下可明显延缓抗坏血酸、可溶性蛋白质、可溶性固形物含量的下降,抑制亚硝酸盐含量的升高。其中,以冷藏PE贮藏方式对保持鲜切白菜的食用品质效果最佳。     

臭氧冷海水对竹筴鱼冷藏品质的影响

为了分析臭氧冷海水处理对冷藏竹筴鱼品质的影响,本文研究了自来水预处理(A)、冷海水预处理(B)、臭氧冷海水预处理(C)的竹筴鱼在4±1℃贮藏条件下的鱼体菌落总数(APC)、p H值、挥发性盐基氮(TVB-N)、硫代巴比妥酸值(TBARS)、色差、质构和感官品质的变化规律。结果显示,在贮藏期间,各预处理竹筴鱼鱼体的菌落总数、TVB-N和b*均随着冷藏时间的延长而上升,在贮藏后期B和C处理对鱼体菌落总数和TVB-N的抑制作用显著高于A处理,且C处理效果显著好于B处理(p0.05)。第10天时,A组鱼体的菌落总数和TVB-N分别达到7.13 log CFU/g和31.43 mg/100 g,超出国家限定标准。同时,竹筴鱼的感官评分随着贮藏时间延长而下降,但B和C组较A组感官评分下降得慢。然而,B和C组鱼体脂肪氧化程度较A组高,说明臭氧和冷海水处理促进了鱼体脂肪的氧化。臭氧冷海水处理对p H值、色度的L*、a*值、质构影响不大。因此,臭氧冷海水处理有利于延缓竹筴鱼鲜度指标的下降,保证竹筴鱼的冷藏品质,延长其货架期。     

Deodorization of Garlic Breath Volatiles by Food and Food Components

The ability of foods and beverages to reduce allyl methyl disulfide, diallyl disulfide, allyl mercaptan, and allyl methyl sulfide on human breath after consumption of raw garlic was examined. The treatments were consumed immediately following raw garlic consumption for breath measurements, or were blended with garlic prior to headspace measurements. Measurements were done using a selected ion flow tube‐mass spectrometer. Chlorophyllin treatment demonstrated no deodorization in comparison to the control. Successful treatments may be due to enzymatic, polyphenolic, or acid deodorization. Enzymatic deodorization involved oxidation of polyphenolic compounds by enzymes, with the oxidized polyphenols causing deodorization. This was the probable mechanism in raw apple, parsley, spinach, and mint treatments. Polyphenolic deodorization involved deodorization by polyphenolic compounds without enzymatic activity. This probably occurred for microwaved apple, green tea, and lemon juice treatments. When pH is below 3.6, the enzyme alliinase is inactivated, which causes a reduction in volatile formation. This was demonstrated in pH‐adjusted headspace measurements. However, the mechanism for volatile reduction on human breath (after volatile formation) is unclear, and may have occurred in soft drink and lemon juice breath treatments. Whey protein was not an effective garlic breath deodorant and had no enzymatic activity, polyphenolic compounds, or acidity. Headspace concentrations did not correlate well to breath treatments.     

Volatile compounds in light, medium, and dark black walnut and their influence on the sensory aromatic profile

Light, medium, and dark colored kernels from 3 different cultivars (Emma K, Kwik Krop, and Sparks 127) and one wild species of black walnut were studied for their aroma volatiles. Solid-phase microextraction-gas chromatography-mass spectrometry was used to determine the aromatic compounds present in the headspace of these samples. Partial least square regression was used to correlate the instrumental aromatic data with the sensory responses, obtained in a previous study, for the same samples. Thirty-four aromatic compounds were found in the black walnut cultivars, highlighting among them the presence of 14 esters. Although more than 50% of the total concentration of volatile compounds, esters were not important compounds in determining the differences in the sensory aromatic profiles of the 3 colors of the nuts. As a general trend, the concentration of total volatile compounds was always significantly higher in light black walnuts than in the medium colored samples; medium colored samples had higher volatile content than the dark black walnuts. The presence of hexanal was related to rancid and acrid aromas and was determined to differentiate the dark black walnuts from the medium and light colored samples. PRACTICAL APPLICATION: The data presented in this article will help understand the aromatic differences between light, medium, and dark colored kernels of domestic and wild black walnut. The aromatic profile of these nuts, not studied until this moment, can be used as a model to develop flavorings and new products by the food industries.     

二氧化氯和臭氧杀菌处理对菜心贮藏品质的影响

为提高菜心贮藏品质,研究二氧化氯(ClO2)、臭氧(O3)两种杀菌剂对菜心贮藏期间的呼吸强度、丙二醛含量、过氧化物酶活等品质指标变化规律的影响。研究发现,与对照组相比,在贮藏期内ClO2和O3对菜心呼吸的影响是先促进后抑制,二者均使菜心呼吸高峰提前到达,但贮藏中后期(6 d^9 d)杀菌组的呼吸强度低于对照组,ClO2对呼吸的抑制优于O3;ClO2和O3提高了菜心贮藏前期的硬度,贮藏后期ClO2组菜心硬度适中;ClO2降低了菜心a*值,有利于保持菜心的绿色;O3对菜心a*值略有提高,对菜心绿色影响不显著;ClO2和O3促使菜心中丙二醛的累积,但量小难以促衰老;ClO2能稳定维持偏低的过氧化物酶活性,抑制苯丙氨酸解氨酶活性,延缓其木质化和衰老,保持品质。综合分析得出,ClO2更适合杀菌处理菜心,货架期可达12 d,具有潜在的应用前景。     

Profiles of volatile compounds and sensory analysis of three blends of coffee: influence of different proportions of Arabica and Robusta and influence of roasting coffee with sugar

One hundred and forty‐six volatile compounds were identified and quantified using a static headspace sampler in three blends of coffee: Arabica/Robusta 80:20 (A80:R20) natural roasted coffee, Arabica/Robusta 20:80 (A20:R80) natural roasted coffee and Arabica/Robusta 20:80 with 50% of Robusta coffee roasted with sugar (A20:R80 50% Torrefacto). The different proportion of Arabica and Robusta coffee in the blend A80:R20 versus A20:R80 influenced the amounts of 20 chemical families of volatile compounds. Aldehydes, ketones, alcohols, pyrroles, pyrazines, furans, thiazoles, thiophenes, esters, oxazoles, lactones, sulphur compounds, pyridines, alkanes, alkenes, phenolic compounds, benzenic compounds, acids, pyranones and terpenes were present in higher quantities in the sample containing 80% of Arabica coffee, whereas sulphur compounds were more abundant in the coffee with 80% of Robusta. Sensory differences were also found between the two blends of coffee in the burnt, caramel, nutty, earthy and roasty notes. Torrefacto coffee, widely consumed in Spain, is obtained by roasting coffee with sugar. Higher quantities of ketones, alcohols, pyrazines, furans, pyridines, alkanes, phenolic compounds, pyranones and terpenes were found in the blend A20:R80 50% Torrefacto coffee versus A20:R80 natural roasted coffee. These differences in the volatile fraction were perceived by our panellists in the intensities of the nutty, roasty, earthy, burnt and caramel notes. © 2002 Society of Chemical Industry     

切分方式对鲜切紫甘蓝营养品质和挥发性风味物质的影响

为研究不同切分方式对鲜切紫甘蓝品质的影响,采用横切及纵切两种方式切分紫甘蓝,比较贮藏前后鲜切紫甘蓝的表观颜色、褐变率、可溶性固形物、酚类物质和花色苷含量及风味品质。结果表明,贮藏9 d后,鲜切紫甘蓝的L~*值和a~*值降低,b~*值增加,褐变率增加,可溶性固形物减少0.27～0.33 Brix,总酚和总花色苷质量分数分别增加2.69～2.78 mg/g和0.06～0.11 mg/g;纵切可有效减缓样品褐变,保持儿茶素、绿原酸、咖啡酸、阿魏酸和奎宁酸等酚类物质含量。电子鼻与挥发性物质分析表明,贮藏9 d后紫甘蓝中的氮氧化合物增加,横切较纵切样品异硫氰酸烯丙酯等含量增加,导致不良风味的产生。研究结果表明,纵向切分可减缓切面褐变,较好地保持紫甘蓝的酚类成分及风味品质。     

Effect of Cheese pH and Temperature on Serum Phase Characteristics of Cream Cheese During Storage

Three 13.6‐kg blocks of cultured cream cheese manufactured on different days were obtained from a commercial source within 2 wk of manufacture. Blocks were sectioned into samples that were randomly assigned to 3 treatments. A model system was used to change cheese pH. One group of samples was exposed to volatile ammonia to increase the pH to about 5.3. A 2nd group was exposed to volatile acetic acid to decrease the pH to about 4.5. A 3rd group served as a control (pH about 4.8). Samples from each pH treatment were vacuum‐packaged and randomly assigned to 1 of 2 storage temperatures: 4 °C and 20 °C. Samples were randomly chosen for analysis after 4, 8, 12, 16, 20, 24, and 28 d of storage and centrifuged at 12500 ±g for 75 min at 25 °C to obtain expressible serum (ES). The ES was analyzed for viscosity at 25 °C. Effects of pH treatment, storage time, and storage temperature were evaluated by analysis of variance (ANOVA) according to a split split‐plot design. The amount of ES increased significantly during storage and was affected by storage temperature and cheese pH. Significantly more ES was obtained at higher temperature and higher pH. Viscosity of ES decreased significantly during storage and was affected by storage temperature and cheese pH. Viscosity decreased more rapidly at higher temperature and higher pH. The data suggest that higher temperature and higher pH resulted in accelerated loss of stabilizer function during storage, possibly due to microbiological degradation of the stabilizer.     

温度及防腐剂对切分包菜浸渍品质的影响

探讨了不同温度及防腐剂对4%食盐溶液浸渍切分包菜品质的影响。测定内容包括pH值、浊度、亚硝酸盐生成量、Vc、总糖和氨基酸含量。结果表明:低温对保持低盐、短期浸渍包菜的感官品质有较好的效果,有利于总糖成分的保存,但Vc主要以氧化型形式存在;添加山梨酸钾不能抑制乳酸菌的活动,对减少亚硝酸盐的生成无显著作用;低盐、短期浸渍包菜的亚硝酸盐生成量小于1mg/kg,远低于常规腌制菜。     

预处理对脱水甘蓝品质的影响

针对脱水甘蓝用葡萄糖和乳糖渗透处理时成本较高的问题，实验找到了一个价格较低、渗透性和脱水性都优于乳糖的添加剂一高麦芽糖浆，并确定了两个工艺条件：直接加固体糖、渗透脱水1h。还研究了使用高麦芽糖浆、乳糖和葡萄糖预处理的甘蓝干燥速率曲线，并研究了其能效性。     

1-MCP对黄金百香果贮藏品质及风味变化的影响

为明确1-甲基环丙烯(1-MCP)对百香果采后品质及风味变化的影响,果实采后用1-MCP (0.8 μL,L-1,12h)处理后,评测常温贮藏过程中果面色泽、果汁糖酸和维生素C (vc)含量变化,并采用气相色谱-离子迁移谱联用(Gas Chromatography-Ion Mobility Spectrometry,G...     

Analysis of factors affecting volatile compound formation in roasted pumpkin seeds with selected ion flow tube-mass spectrometry (SIFT-MS) and sensory analysis

Pumpkin (Cucurbita pepo and maxima) seeds are uniquely flavored and commonly consumed as a healthy roasted snack. The objective was to determine dominant volatiles in raw and roasted pumpkin seeds, and the effect of seed coat, moisture content, fatty acid ratio, total lipids, reducing sugars, and harvest year on volatile formation. Sensory was conducted to evaluate overall liking of seed variety and texture. Seed processing included extraction from the fruit, dehydration, and roasting (150 °C). Oil extraction was done using soxhlet, fatty acid profile using Gas Chromatography Flame Ionization Detector, and reducing sugars using 3,5-dinitrosalicylic acid and UV-spectroscopy. Headspace analysis of seeds was performed by selected ion flow tube-mass spectrometry (SIFT-MS). Volatiles dominating in raw pumpkin seeds were lipid aldehydes, ethyl acetate, 2,3-butandione, and dimethylsulfide. Compounds contributing to roasted aroma include alkylpyrazines and Strecker and lipid aldehydes. Overall, hull-less seeds had higher volatile lipid aldehydes and Strecker aldehydes. Seeds dehydrated to a moisture content of 6.5% before roasting had higher initial and final volatile concentrations than seeds starting at 50% moisture. Higher oil content resulted in higher lipid aldehyde formation during roasting with a moderate correlation between free fatty acid ratio and corresponding lipid aldehyde. Harvest year (2009 compared with 2010) had a significant impact on volatile formation in hull-less seeds, but not as much as variety differences. No significant correlation was found between reducing sugars and volatile formation. Sensory showed that hull-less seeds were liked significantly more than hulled seeds. PRACTICAL APPLICATION: Elucidation of aromatic flavor development during roasting with SIFT-MS provides information on flavor release and offers better control during processing. Knowledge of volatiles in raw and roasted pumpkin seeds and effects of seed coat, moisture content, seed composition, and harvest date will allow for better control over the production/storage/transportation process and a more educated decision during selection of a variety for production of pumpkin seeds in the snack food industry.     

鱼体初始中心温度对智利竹筴鱼冷藏品质的影响

为了分析不同鱼体初始中心温度对冷藏智利竹筴鱼品质的影响,本文研究了初始中心温度为0、3和6℃的智利竹筴鱼(各处理依次标记为A、B和C)在4±1℃贮藏条件下的鱼体pH值、挥发性盐基氮(TVB-N)、三甲胺(TMA-N)、硫代巴比妥酸值(TBARS)和感官品质的变化规律。结果显示,在贮藏期间,各预处理竹筴鱼鱼体的pH值、TVB-N、TMA-N和TBARS均随着冷藏时间的延长而上升,且C组至第6 d时,其pH值、TVB-N、TMA-N和TBARS分别达到6.13、0.29 mg/g、0.13 mg/g、7.12 mg/kg,显著高于A、B组的结果(p0.05)。此外,竹筴鱼的感官评分与贮藏时间存在负相关性,且鱼体初始中心温度越低,其感官评分下降得越慢。研究表明,智利竹筴鱼鱼体初始中心温度越低,越有利于延缓鱼体各个鲜度指标的下降,从而保证竹筴鱼的冷藏品质,延长其货架期。     

臭氧联合植酸处理对鲜切水果甘蓝品质的影响

为了提高鲜切水果甘蓝的品质、延长其货架期,本实验采用臭氧处理（30?mg/L,10?min）、植酸浸泡处理（0.5?mmol/L,15?min）、臭氧联合植酸处理（先0.5?mmol/L植酸浸泡15?min,然后30?mg/L臭氧处理10?min）对鲜切水果甘蓝进行保鲜研究,以未经任何处理的样品为对照组。将水果甘蓝切分成2?cm×5?cm的小块,分别经上述处理后装入聚乙烯保鲜袋中,置于4?℃冷库中贮藏,分别测定第0、2、4、6、8天的生理生化指标和菌落总数。结果表明：贮藏第8天时,臭氧联合植酸处理组的可溶性糖、可溶性蛋白含量最高,分别是对照组的1.21、1.28?倍;同时保持了较高的抗坏血酸、硫代葡萄糖苷和异硫氰酸盐的含量;并提高了总酚含量、苯丙氨酸解氨酶、超氧化物歧化酶活力,抑制了过氧化物酶、过氧化氢酶的活力;菌落总数相比对照组低2.10（lg（CFU/g））。综上所述,臭氧联合植酸处理能较好地保持鲜切水果甘蓝的品质,延长其货架期。     

TBA Values, Sensory Characteristics, and Volatiles in Ground Pork During Long-term Frozen Storage: Effects of Packaging

Ground pork (30% fat) was packaged in vacuum bags (V), polyvinyl chloride film (P), Saran Wrap?(S), aluminum foil (A), or Saran?-aluminum foil combination (SA) and frozen at - 17°C for 13, 26, and 39 wk. Samples were analyzed for TBA value and pH. Volatiles were steam distilled, volatilized at 60°C, and 1 mL samples of headspace gas was analyzed using gas chromatography and mass spectrometry. Spectra for individual peaks on the total ion chromatograms were identified with spectra from known standards. Ground pork (cooked to 75°C) was evaluated by a trained sensory panel for flavor and texture. Rancid and acid odor and flavor scores and TBA values increased over time regardless of packaging treatment; however, V-packaged pork had lower scores and P-packaged had higher scores at all time periods than did that in other materials. Eighteen volatiles were identified and quantified using GC/MS; 3-hydroxy-2-butanone had the highest correlation coefficients with TBA value, odor, and flavor scores.     

预处理和贮藏条件对脱水甘蓝表面返霜的影响

添加葡萄糖的脱水甘蓝在贮藏过程中葡萄糖极易从甘蓝内部迁移到表面．实验结果表明，渗糖处理时添加一定量的乳糖和高麦芽糖浆代替葡萄糖，对延长脱水甘蓝的返霜期有良好的效果，高麦芽糖浆对延长脱水甘蓝返霜的效果明显好于乳糖．实验还研究了热烫时间、贮藏环境的相对湿度对葡萄糖迁移影响的规律．热烫90s、贮藏在较低的环境湿度下均有利于延长脱水甘蓝的返霜天数．