烟丝挥发性香味物质与卷烟感官质量的相关性研究

选取中国市场价为每条200～300元的卷烟(30个样品)为研究对象,采用同时蒸馏萃取法测定其挥发性香味物质含量,并对其感官质量进行评价。运用简单相关分析、逐步回归分析和主成分分析对各项指标间的相关性进行了统计分析。结果表明:不同卷烟烟丝中的总香味含量,各类香味物质和感官评价结果符合正态分布;不同卷烟烟丝中致香成分和感官质量之间具有一定的相关性,其中,卷烟香气和杂气与烟丝所含的总香味物质以及大部分香味物质呈显著正相关。得到香气和谐调性指标的预测模型方程,经显著性测验均达到了极显著水平。总香味物质含量、新植二烯、酮类、醛类和酚类是主要的影响因子,其中,总香味物质含量是影响卷烟感官质量的主体因子。     

Analysis of spinning process using the Taguchi method. Part I: Effect of spinning process variables on fibre orientation and tenacities of sliver and roving

Abstract

The effect of drafts at different stages of spinning process on fibre orientation and tenacities of sliver and roving has been studied by using Taguchi method and analysis of variance. Among all the fibre orientation parameters analysed the ‘coefficient of relative fibre parallelization (K _rp)’ influenced the maximum with change in process variables. Further, the equation used for calculation of K _rp was critically analyzed and modified for a better explanation of fibre orientation. The fibre orientation in sliver and roving was also studied in terms of a new index of measurement of fibre straightness along the length. Increase in lap hank and card draft increases proportion of curved fibre ends (ρ) and decreases K _rpm in card and breaker sliver. However, the improvement in K _rpm is seen to be higher in finisher sliver and roving produced by finer lap hank and higher card draft in subsequent processes. Increase in lap hank, card draft and draft/doublings decrease the FSI in slivers. The lower speed frame draft tends to decrease fibre straightening index (FSI) of roving. Further, a combination of K _rpm, ρ and FSI values is seen to decide the strength of slivers.     

Grape seed flour is a viable ingredient to improve the nutritional profile and reduce lipid oxidation of frankfurters

In this study, grape seed flour (GSF) obtained from wine by-products was incorporated into frankfurters at seven concentrations (0, 0.5, 1, 2, 3, 4, and 5%) and the effects occurred on physical, nutritional and sensory characteristics of the products were investigated. The colour values (L*, a* and b*) of frankfurters generally decreased (p < 0.05) on account of the increasing amount of GSF. The utilization of this flour also led to a decline in the oxidation level of the products (p < 0.05), probably due to its antioxidant content. The increment of GSF in the frankfurters enhanced the protein, total dietary fibre and water holding capacity of the treatments (p < 0.05). Although the level of GSF above 0.5% reduced overall acceptability, the frankfurters containing the level up to 2% received scores above the average. The evaluation of wine by-products in the production of healthier and functional frankfurters has been achieved by the study, but further research is necessary to improve palatability of the products.     

Combining culture‐dependent and culture‐independent molecular methods for the isolation and purification of a potentially novel anaerobic species from pit mud in a Chinese liquor distillery

Strain S12–27–1‐3‐5 (a potentially novel anaerobic species) with a 16S rRNA sequence homology of <97% was isolated and purified from pit mud by combining culture‐dependent and culture‐independent molecular methods, such as cloning of 16S rRNA, amplified rRNA restriction analysis, and denaturing gradient gel electrophoresis (DGGE). Phylogenetic analysis of the 16S rRNA gene indicated that strain S12–27–1‐3‐5 was related to Aminobacterium mobile strain ILE‐3 DSM 12262^T and Aminobacterium colombiense strain DSM 12261^T (95 and 96% similarity value, respectively). The results verified that cloning of the 16S rRNA was efficient to identify whether a potentially new bacterial taxon existed in impure isolates and that the DGGE method was a powerful tool for screening the target bacteria and for identifying duplicate strains. Therefore, the application of the culture‐independent molecular methods for the isolation and purification of a potentially novel species was effective. Strain S12–27–1‐3‐5 (= DSM 27871 = JCM 19605 = CICC 10731^T) was an anaerobic amino acid‐degrading bacterium. The results of fermentation experiments demonstrated that strain S12–27–1‐3‐5 produced volatile fatty acids (VFAs) and the presence of Methanosarcina barkeri enhanced the generation of VFAs, which contribute to the aroma composition of Chinese liquor. This work could enrich the species resources and promote the development and utilization of an uncultured species. Copyright © 2016 The Institute of Brewing & Distilling     

Water retention properties and solubility of the myofibrillar proteins: Interrelationships and possible value as indicators of the gel strength in cod surimi by a multivariate data analysis

The quality of surimi made from fish aged on ice for up to 14 days was evaluated by compression test on a model product. Water holding capacity (WHC) and pH in the fish mince, and protein content, pH, salt solubility of the myofibrillar proteins and hydration index of the insoluble proteins (HUP) in the surimi, were determined. Their interrelationships and utility as indicators of surimi quality were evaluated by a multivariate data analysis. The main tendencies of variation among the chemical parameters were examined by the use of principal component analysis. Correlations between the chemical parameters (X-variables) and the gel strength of surimis (Y-variable) were studied by the use of partial least squares regression. Age of the raw material and protein content of the surimi seemed to be the main determinants of the gel strength. Among the remaining variables only HIIP showed a potential value as indicator of the gel strength. WHC and HIIP seemed to reflect two different water retention properties of the proteins.     

Nitrite and nitrate in fresh meats: a contribution to the estimation of admissible maximum limits to introduce in directive 95/2/EC

Nitrite and nitrate are food preservatives not allowed in fresh meat preparations. Two hundred fresh meat samples were analysed to evaluate the natural presence of nitrite and nitrate and estimate the maximum concentrations to considerate as ‘natural’ and to admit in fresh meat preparations. The analyses were carried out by a validated ion chromatography method, and the ‘positive’ samples were confirmed by an alternative ion chromatography method. Nitrite residues were not detected. Quantifiable nitrate concentrations, ranging from 10.2 to 36.5 mg kg^?1, were found in nineteen samples. In chicken meat samples, nitrate residues were not detected. Taking into account the distribution of nitrate concentrations, it is possible to suggest a maximum admissible limit of 30.0 mg kg^?1 in beef and pork meats; in equine meats, this limit may be increased to 40.0 mg kg^?1. Below these values, the samples can be considered as ‘compliant’.     

Short communication: Comparison of bulk milk, yield-corrected, and average somatic cell counts as parameters to summarize the subclinical mastitis situation in a dairy herd

In this study, the correlation was determined between the prevalence of high cow-level somatic cell count (SCC >250,000 cells/mL), a summary of the subclinical mastitis situation in a dairy herd, and 3 average herd SCC parameters: bulk milk SCC (BMSCC), yield-corrected test-day SCC (CHSCC), and the arithmetic average test-day SCC (HSCC) of the lactating herd. The herd prevalence of cows with an SCC of >250,000 cells/mL was calculated by using Dairy Herd Improvement data. Herds were included if BMSCC was sampled within 2 d of the Dairy Herd Improvement test day and if the BMSCC did not exceed 400,000 cells/mL. The interval between sampling, 0, 1, or 2 d, did not significantly influence the correlation between BMSCC and the prevalence of high SCC. The correlations between the prevalence of high SCC and BMSCC, yield-corrected test-day SCC, and HSCC, examined by using a linear regression model, were 0.64, 0.78, and 0.89, respectively. Therefore, it can be concluded that, based on the highest correlation, HSCC is a more appropriate parameter than BMSCC to summarize the average herd subclinical mastitis situation in a dairy herd.