Effect of sulphur dioxide on microbial growth in refrigerated pre-peeled potatoes packaged in plastic films

Microbial growth in pre-peeled potatoes was analysed to determine the simultaneous effect of sodium bisulphite concentration (105–219 mg kg^?1), storage temperature (4, 7 and 10°C) and gaseous permeability of the packaging plastic film (polyethylene and EVA—SARAN—EVA used in vacuum) on product storage life. Composition of the microbial flora was determined at the beginning and the end of the storage period, and the principal microorganisms causing spoilage of the product were observed to be Pseudomonas spp and Enterobacteriaceae. Lag phase duration and specific rate constants were determined for these microorganisms in samples stored at each condition. In polyethylene-packaged samples microbial growth was observed at various temperatures and SO₂ concentrations were tested. With vacuum packaging in low oxygen permeability films and residues of 100 mg SO₂ kg^?1, microbial counts were maintained in the lag phase; larger residues produced microbial inhibition at 4, 7 and 10°C.     

Effect of organic growing systems on sensory quality and chemical composition of tomatoes

Tomato plants were grown in the greenhouse in the soil, in confined beds, or in combined beds where the roots could also develop in the soil outside the bed. The beds were filled with compost based on clover grass hay, deep litter and peat and harvested in early summer and autumn in 2002 and 2003, and in the soil treatment the same compost was incorporated into the soil. The tomato fruit quality was assessed by sensory analysis and content of chemical components as, e.g. dry matter, soluble solids, citric acids and volatile components. The content of minerals was mainly determined to evaluate possible limitations in nutrient supply. Due to only minor effects of growing systems on sensory quality and chemical composition of tomato fruits it is concluded that it is possible to produce tomato fruits in confined and combined soil bed systems without any loss in eating quality. Actually the results indicate that a slight increase in quality of tomatoes from the confined and combined systems is obtained. The present result points to the fact that confined and combined growing systems may be new relevant commercial growing systems, in which the quality of tomatoes seems to be ensured, and in which nutrient loss and root diseases contamination can be reduced.     

咖啡豆的化学组分差异与感官品质的相关性分析

为了探讨咖啡中化学组分与感官品质之间的关系,通过测定7种不同产区咖啡豆的蛋白质、还原糖、绿原酸、葫芦巴碱和咖啡因含量以及咖啡液pH,分析这些组分含量的多少与感官品质之间的关系。经Pearson线性相关性检验,咖啡感官评分高低与咖啡因含量和葫芦巴碱含量的线性相关性具有显著性,均成负相关,相关系数分别为r=0.855和r=0.366。同时咖啡感官好的风味品质与咖啡因损失量(r=0.897)、葫芦巴碱损失量(r=0.848)、绿原酸损失量(r=0.933)、还原糖损失量(r=0.713)正相关性均为极显著,与蛋白质损失量的线性相关性不显著。另外,7种不同产区咖啡豆,不同烘焙程度和不同品种咖啡间pH的差异不大。      

Identification of chemical markers for the sensory shelf-life of saveloy

The aroma composition, the microbial composition and the sensory profile were measured in sliced saveloy samples packed in modified atmosphere (MA). The main objective was to identify aroma compounds with potential as chemical markers to identify the sensory changes of saveloy. The 60 aroma compounds isolated from the saveloy samples by dynamic headspace extraction and measured by Gas Chromatography Mass Spectrometry (GC-MS) were used to model the sensory attributes sour&old odour and meaty odour using partial least squares regression (PLS). 2- and 3-methylbutanal, 2- and 3-methylbutanol, acetoin and diacetyl were found to have the highest impact on both sour&old odour and meaty odour of the samples. The results show that these four aroma compounds have high potential as chemical markers for the sensory shelf-life of sliced and MA-packed saveloy.     

Physicochemical and sensory quality of several commercial Brazilian chocolate milk beverages

Five brands of Brazilian chocolate milk were subjected to physicochemical and acceptability analysis. The moisture content, fat content, pH and soluble solids content varied between 78.35 and 84.27 g/100 mL, 1.68 and 3.08 g/100 mL, 7.11 and 7.44, 14.0 and 19.0° Brix, respectively, while the ash contents and % lactic acid equivalents were similar. Four of the tested brands had acceptable scores in all attributes; however, one had lower acceptability scores and lower values for luminosity, chromaticity, b* and hue angle, which are potential indicators of the sensory quality. Strong chocolate aroma, strong chocolate flavour, strong brown colour, brightness and sandiness may be used as indicators of low acceptability for chocolate milk.     

Effect of ungutting on microbiological, chemical and sensory properties of aquacultured sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) stored in ice

The effect of ungutting on microbiological, chemical and sensory properties of aquacultured sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) stored in ice were studied. The total viable mesophilic and psychrophilic bacterial counts increased throughout the storage period of ungutted sea bream and sea bass. Mesophilic counts of ungutted sea bream and sea bass reached 7.39 log cfu/g and 7.26 log cfu/g after 9 days. At the end of the storage period of 14 days; TVB-N, TBA, TMA-N values of ungutted sea bream were determined as 37.5±0.51 mg/100 g, 3.82±0.03 mg MA/kg, 7.73±0.25 mg/100 g, respectively. TVB-N, TBA, TMA-N values of ungutted sea bass were reached 35.4±0.9 mg/100 g, 3.75±0.81 mg MA/kg, 6.94±0.08 mg/100 g on day 14th, respectively. Result of this study indicates that the shelf life of whole ungutted sea bream stored in ice as determined by the overall acceptability sensory scores, chemical quality and microbiological data is 12, 9 and 9 days, respectively. Each chemical, sensory and microbiological results for sea bream showed us that there was a correlation and similarity, and day 9 was the beginning of spoilage. Whole ungutted sea bass stored in ice as chemical results for sea bass showed us that day 7 was the beginning of spoilage and for sea bream day 9 was the beginning of spoilage.     

Effect of pork lard content on the chemical, microbiological and sensory properties of a typical fermented meat product (Pitina) obtained from Alpagota sheep

The aim was to investigate the physicochemical, microbiological and sensory properties of Pitina, a typical fermented meat product and evaluate the effect of two levels of pork lard content (Low Fat, LF, 10% vs. High Fat, HF, 30%) on its attributes. HF attained lower pH than LF Pitina, which reached lower water activity. LAB comprised the major flora with substantial counts of micrococci, enterococci and mould and yeast. Gram negative Enterobacteria were recovered as coliforms and faecal coliforms. Listeria monocytogenes was also isolated. The lard level influenced the count of micrococci and some sensory attributes. LF attained higher scores for both hardness and cohesiveness and differed from HF in having a more marked odour of ewe and smoke and sweeter taste. HF had a more pronounced odour and taste of garlic and mould than LF.     

烟支规格对卷烟物理、烟气、燃吸特性及感官质量的影响

为探究烟支规格对卷烟质量的影响,在烟丝原料、填充密度、卷烟纸透气度、接装纸规格、丝束材料以及滤棒吸阻条件相同的情况下卷制4种规格卷烟[烟支规格(烟支圆周×长度):常规(24.3 mm×84 mm)、22 mm卷烟(22 mm×84 mm)、中支(20 mm×89 mm)、细支(16.9 mm×97 mm)],检测其物理...     

Characterisation of aroma‐active compounds,chemical and sensory properties of acid‐coagulated cheese: Circassian cheese

The objectives of this study were to determine basic composition, aroma and sensory characteristics of Circassian cheese. Seven Circassian cheeses were provided by local producers. Aroma compounds were extracted by using solid‐phase microextraction procedure and determined by gas chromatography‐olfactometry system. Water‐soluble, trichloroacetic acid‐soluble and phosphotungstic acid‐soluble nitrogen fractions ranged between 2.30–29.35%, 2.48–9.96% and 3.33–6.26%, respectively. Diacetyl, butyric acid, 2‐acetyl‐1‐pyrroline, 1‐octen‐3‐one and methional were identified at high intensities in cheeses. In addition, ‘cooked’, ‘whey’, ‘creamy’ and ‘fermented’ were defined as characteristic flavour terms for Circassian cheeses.     

Structure of pectin in relation to abnormal hardness after cooking in pre-peeled, cool-stored potatoes

Unacceptable hard tissue can be detected in pre-peeled potatoes after cooking. Pectin methyl esterase (PME) has been suspected to facilitate formation of Ca-bridges between pectin molecules by deesterification of the uronic acids. But this has also been questioned, due to the low storage temperature of the peeled tubers, optimum of PME being 50-70 °C. Hardness in tubers was induced by several packaging methods. Annual and seasonal variations were observed. In the work, analysis of nonstarch polysaccharides (NSP) are considered representative of the pectin content. Analyses revealed an increase in insoluble NSP during storage after peeling and cooking, and a decrease in branching (arabinose, galactose) and degree of methyl esterification of total NSP, in both fresh and cooked tissue, dependant on storage period. Reduction of steric hindrance by debranching of the pectin molecules as well as a PME-induced increase of possible Ca-cross-linking sites may favor hardening of the tissue. The microscopy does not show any pectin changes until after cooking, but the chemical data do. This suggests that hardening, at least partly, is due to the removal of methyl ester groups, as well as galactose and arabinose in the side chains. The Ca-bridges can probably not be formed until sufficient calcium is released from the starch during gelatination.     

Effect of conjugated linoleic acid supplementation on the microbial,physical, chemical and sensory properties of yoghurt

The aim of this study was to determine the effect of synthetic conjugated linoleic acid (CLA) supplementation on the quality of yoghurt. Yoghurt was prepared by adding CLA to create yoghurt with 0%, 25%, 50% and 100% w/w of the recommended dietary allowance for CLA. CLA inclusion had no effect on the viability of the yoghurt lactic acid bacteria. Physical properties such as viscosity and pH increased with increased CLA levels. CLA inclusion had a significant effect on the fatty acid composition of the yoghurt. Yoghurts from all four treatments were found acceptable by a consumer panel.     

切丝宽度对中支卷烟烟丝结构、烟支理化指标及感官质量的影响

为了探究切丝宽度对中支卷烟烟丝结构、烟支物理指标、烟气指标、主流烟气粒相物致香成分含量及感官质量的影响,在切丝宽度分别为0.80、0.85、0.90、0.95、1.00 mm时,采用相同的烟丝加工和卷制条件卷制成烟支圆周为22 mm的中支卷烟,分析了烟丝结构和成品烟支物理指标、烟气指标、主流烟气粒相物致香成分含量和感官质量。结果表明:①切丝宽度由0.80 mm增加至1.00 mm,整丝率提高2.85百分点,碎丝率降低0.80百分点,烟支圆周呈现增加的趋势,烟支吸阻呈现逐渐降低的趋势,烟支吸阻降低164 Pa。切丝宽度为0.85 mm时,烟支单支质量标准偏差和吸阻标准偏差最小。②烟气CO量和切丝宽度之间呈现显著负相关;随着切丝宽度增加,烟气烟碱量增大,变化在0.04 mg/支范围内;烟气焦油量先增大后减小,在切丝宽度为0.95 mm时达到最大。③烟气粒相物致香成分中羰基类化合物、杂环类化合物、酚类化合物含量及致香成分总量,均呈现先增加后降低并趋于稳定的趋势,在切丝宽度为0.85 mm时达到最大。④烟支整体感官质量得分和单项指标得分随着切丝宽度的增加均呈现下降的趋势,切丝宽度为0.80~0.90 mm的样品感官质量明显好于切丝宽度为0.95 mm和1.00 mm的样品。     

KC-2A膨胀介质对烟丝化学成分和感官品质的影响

研究了新型膨胀介质(KC -2A)在使用不同膨胀方法(微波、蒸汽)时,对烟草化学成分、感官品质的影响,并对膨胀前后烟丝化学成分、烟气化学成分的变化进行了测定,对膨胀前后的感官品质进行了评价.结果表明:新型环保介质烟丝膨胀工艺的膨胀烟丝各项理化指标与目前国内膨胀烟丝指标相当,其中微波膨胀的烟丝香气略好.     

Microbiological and sensory quality changes in blood pancakes and cooked ring sausage during storage

The microbiological and sensory quality of blood pancakes and vacuum-packed cooked ring sausages were studied one day after production, on the sell-by date and one week after the sell-by date. Samples were taken straight from 5 manufacturing plants, stored at 4°C and analyzed by 3 different laboratories using similar methods. Blood pancakes contained high numbers of aerobic organisms and yeasts. The principal sensory defects were visible mould spots, rancid odour and musty taste. A correlation between taste and microbiological counts was observed. Bacillus cereus was observed in some samples and may constitute a potential health hazard when temperature abuse occurs. Cooked ring sausages showed good microbiological and sensory quality after production. Aerobic plate counts and lactobacilli numbers increased during storage. The main defects in sensory analysis were fermented, sour aroma and taste. No correlation between taste and microbiological counts could be determined. The store shelf-lives (sell-by periods) of blood pancakes and cooked ring sausages set by the manufacturers, 7–11 and 20–28 days, respectively, can be considered overly optimistic. Differences between laboratories were observed in the sensory analyses.     

Phytochemical,sensory attributes and aroma stability of dense phase carbon dioxide processed Hibiscus sabdariffa beverage during storage

The effect of dense phase carbon dioxide (DPCD) processing (34.5 MPa, 8% CO₂, 6.5 min, and 40 °C) on phytochemical, sensory and aroma compounds of hibiscus beverage was compared to a conventional thermal process (HTST) (75 °C for 15 s) and a control (untreated beverage) during refrigerated storage (4 °C). The overall likeability of the hibiscus beverage for all treatments was not affected by storage up to week 5. DPCD process retained more aroma volatiles as compared to HTST. Aroma profiles in the beverages were mainly composed of alcohols and aldehydes with 1-octen-3-ol, decanal, octanal, 1-hexanol, and nonanal as the compounds with the highest relative percentage peak areas. A loss of only 9% anthocyanins was observed for the DPCD processed hibiscus beverage. Phytochemical profiles in the hibiscus beverage included caffeoylquinic acids, anthocyanins, and flavonols. No major changes in total phenolics and antioxidant capacity occurred during the 14 weeks of storage.     

Effect of fat quality on sausage processing,texture, and sensory characteristics

Fresh pork sausage was manufactured to determine the effects of animal diet (unsaturated or control) and inclusion of corn oil during processing (0% and 14% fat replacement). Bologna was manufactured to investigate only diet effects. Processing, textural, sensory, visual, and storage characteristics were evaluated. Processing yield was improved 2.9 percentage units in fresh sausage but reduced 1.8 units in bologna in unsaturated compared with control diets. Break strength of fresh sausage was reduced 0.6 kg by oil inclusion. Both unsaturated fat and including oil during processing resulted in softer texture of fresh sausage, while increased unsaturation in bologna resulted in firmer or unchanged textural properties. Fresh sausage with oil was lighter colored (5.3 L* units increased) with more fat smearing. In fresh sausage, lipid oxidation remained below 1 mg/kg MDA during 12 weeks frozen storage. Overall, changes in fat quality minimally affected sausage quality, likely providing acceptable products to consumers.     

Effects of muscle cortisol concentration on muscle fiber characteristics, pork quality, and sensory quality of cooked pork

The effect of muscle cortisol concentration on muscle fiber characteristics and technological and sensory quality of pork was investigated. With the exception of the percentage of type IIA fibers, muscle fiber characteristics were not associated to cortisol levels. However, muscle cortisol concentration was positively associated with muscle pH(24h) (r = 0.23, P<0.05) and negatively associated with drip loss (r = -0.49, P<0.001), lightness (r = -0.24, P<0.05), shear force (r = -0.25, P<0.05), and texture profile analysis-hardness (r = -0.35, P<0.01). Additionally, the water-holding capacity of meat samples was affected by cortisol levels, with lower cortisol concentrations associated with less tender samples. These results indicate that the concentration of cortisol in the muscle is related with meat quality as well as the sensory quality of cooked pork.     

粳米品质特性及与感官质量关系研究

为明确东北地区不同品种粳米品质差异,找出影响感官质量的关键因素,以稻花香二号、盐丰和辽星大米为研究对象,对其外观特性、理化性质、质构特性、蒸煮特性、香气和感官评价进行分析。结果表明:L^*、a^*、b^*、弹性、黏着性、咀嚼性、吸水率、pH值没有显著性差异(P>0.05),含水量、蛋白质含量、脂肪含量、脂肪酸值、巯基含量、硬度、回复性和膨胀性则差异显著(P<0.05)。电子鼻判别因子分析对3种大米区分明显。GC-MS共鉴定出53种化合物,其中稻花香二号、盐丰和辽星中分别检测到38、28、28种香气成分,有15种物质在3种大米中同时出现,OAV法进一步得到壬醛、癸醛等7种香气活性物质。感官评价综合分值从高到低依次为稻花香二号、辽星和盐丰,其中脂肪含量和脂肪酸值与感官综合评分呈显著负相关,巯基含量、硬度和黏着性与感官综合评分呈显著正相关。