Effect of the Inclusion of Chestnut in the Finishing Diet on Volatile Compounds of Dry-Cured Ham from Celta Pig Breed

The effect of the inclusion of chestnut in pigs ifnishing diet on volatile compounds of dry-cured Celta ham was studied. Twelve hams of each type （from three different pigs ifnishing diets：concentrate （CO）, mixed （MI） and chestnut （CH）） were used. Volatiles were extracted using a purge-and-trap method and analyzed by gas chromatography/mass spectrometry （GC/MS）. Thirty-nine volatile compounds were identified in dry-cured Celta ham samples. Most abundant volatiles in ham samples were aldehydes, which represented respectively, 53% （CO）, 51% （MI） and 46% （CH） of the total volatile composition. With the exception of 2-butenal, 2-methyl, all aldehydes were affected by feeding system. On the other hand, hydrocarbons n-alkanes were the second major group in the volatile proifle of dry-cured Celta hams and represented 28.9, 35.7 and 32.4%of the total volatile composition for CO, MI and CH groups, respectively. Ham samples from chestnut group showed a higher content of alcohols and this result could be related with the inclusion of chestnut in the ifnishing diet of pigs. Principal component analysis showed a good separation among groups. The discriminant analysis selected eight variables （butanoic acid, hexanal, octanal, nonenal （E）, decenal （E）, tetradecane, decane trimethyl and pyridine 2-methyl） and calculated two discriminating functions to predict if chestnut has been included in the ifnishing diet. Thus, it was possible to discriminate between groups fed with ifnishing diets containing chestnuts in their composition （mixed and chestnut group）.

Study Progress on Pests in Dry-cured Ham

Dry-cured ham can become infested with pests during the curing and ag-ing process, which not only damages the ham quality, but also causes economic loss. The advance of study on the effects of ham pests on the ham quality, the main species and distributions of ham pests in process of dry-cured ham were intro-duced in this article.

Evaluation and selection of yeasts as potential aroma enhancers for the production of dry-cured ham

Yeasts play a critical role in the flavor formation of dry-cured ham.In this study,41 yeast isolates from the dry-cured ham at different processing stages were evaluated for their technological properties.Debaryomyces hansenii was the most dominant yeast and has been detected at each phase of dry-cured ham,followed by Candida zeylanoides which was mainly detected in salting phase.Yarrowia bubula and Yarrowia alimentaria were found at the first two-phase of dry-cured ham.All isolates of yeast showed enzymatic activities against milk protein and tributyrin,while only 4 strains displayed proteolytic activity on meat protein.Yeast strains were grown in a meat model medium and volatile compounds were identified.The result showed that inoculated yeast strains could promote the production of volatiles and there were significant differences among strains.D.hansenii S25 showed the highest production of volatile compounds,followed by the strain C.zeylanoides C4.D.hansenii S25 was the highest producer of alcohols showing the highest production of benzeneethanol and 3-(methylthio)-1-propanol.Based on OAV and PLS analysis,D.hansenii S25 was strongly correlated with overall flavor and key volatile compounds of dry-cured ham,which could be selected as potential starter cultures.

Inhibition of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase enzyme by dipeptides identified in dry-cured ham

High cholesterolemia is a key risk factor for the development of cardiovascular diseases,which are the main cause of mortality in developed countries.Most therapies are focused on the modulation of its biosynthesis through 3-hydroxy-3-methylglutaryl-coenzyme A reductase(HMG-CoAR)inhibitors.In this sense,food-derived bioactive peptides might act as promising health alternatives through their ability to interact with crucial enzymes involved in metabolic pathways,avoiding the adverse effects of synthetic drugs.Dry-cured ham has been widely described as an important source of naturally-generated bioactive peptides exerting ACEI-inhibitory activity,antioxidant activity,and anti-inflammatory activity between others.Based on these findings,the aim of this work was to assess,for the first time,the in vitro inhibitory activity of HMG-CoAR exerted by dipeptides generated during the manufacturing of dry-cured ham,previously described with relevant roles on other bioactivities.The in vitro inhibitory activity of the dipeptides was assessed by measuring the substrate consumption rate of the 3-hydroxy-3-methylglutaryl CoA reductase in their presence,with the following pertinent calculations.Further research was carried out to estimate the possible interactions of the most bioactive dipeptides with the enzyme by performing in silico analysis consisting of molecular docking approaches.Main findings showed DA,DD,EE,ES,and LL dipeptides as main HMG-CoAR inhibitors.Additionally,computational analysis indicated statin-like interactions of the dipeptides with HMG-CoAR.This study reveals,for the first time,the hypocholesterolemic potential of dry-cured ham-derived dipeptides and,at the same time,converges in the same vein as many reports that experimentally argue the cardiovascular benefits of dry-cured ham consumption due to its bioactive peptide content.

Elucidation of potential relationship between endogenous proteases and key flavor substances in dry-cured pork coppa

Dry-cured meat products are considerably popular around the world due to unique flavor.Proteolysis is one of the enzymatic reactions from which flavor substances are derived,which is affected by endogenous proteases.The purpose aimed to reveal the potential relationship between endogenous proteases and key flavor substances in dry-cured pork coppa in this paper.The dynamic changes of endogenous proteases activity,free amino acids,and volatiles during dry-cured pork coppa processing were characterized.The results showed that 5 kinds of free amino acids,Glu,Lys,Val,Ala,and Leu,were identified as significant contributors to taste.Meanwhile,key volatiles,such as hexanal,nonanal,octanal,benzaldehyde,3-methyl butanoic acid,2-methyl propanoic acid,and ethyl octanoate,greatly contributed to the flavor characteristics of dry-cured pork coppa.Further partial correlation analysis was performed to better elucidate the relationship among parameters.The results revealed that close relationship between endogenous proteases and key substances.RAP not only significantly affected the accumulation of key active-amino acids,but also affected the accumulation of ethyl octanoate,2,3-pentanedione,and 2,3-octanedione by regulating the accumulation of octanoic acid and Leu.In addition,cathepsin B and D,DPP II,DPP IV and RAP notably affected accumulation of hexanal.

The relevance of dipeptides and tripeptides in the bioactivity and taste of dry-cured ham

Dry-cured ham has been described as a good source of bioactive peptides and taste-active compounds.Some of them are dipeptides and tripeptides that are released in a large amount from different muscle proteins due to the action of exopeptidases during the dry-cured ham processing.The potential of dipeptides and tripeptides to exert bioactivities and impart taste characteristics to dry-cured ham has been evaluated using the BIOPEP database,since in silico approaches are a time-and cost-effective alternative to empirical approaches.Most of the studied dipeptides and tripeptides showed ACE and DPP inhibitory activities as well as imparted bitter taste.In fact,more than one bioactivity and/or taste could be assigned to a given peptide sequence,and there could be a correlation between both,like ACE inhibitory and bitter EA,EI and LG peptides.Furthermore,several dipeptides such as EK,KP,LA,PL,PP,RG,and VE,among others,were found to be multifunctional(ACE and DPP IV inhibitory)which would be determined by their structure,sequence and amino acid composition.In silico analysis evidences the relevance of dipeptides and tripeptides in the bioactivity and taste of dry-cured hams,but further empirical assays including in vitro and in vivo studies are necessary to confirm such theoretical results.Possible degradation of the small peptides during gastrointestinal digestion and intestinal absorption as well as interactions with the food matrix could reduce their bioavailability and bioaccessibility,and modify their biological activities.

基于Hamming距离和量子搜索算法的联想分类器设计

针对现有联想分类器不能存储重复样本的问题,提出一种基于Hamming距离和量子搜索算法的量子联想分类器设计方法,并给出联想分类器存储和分类的线路图.该方法需提前准备5组量子比特,分别对Hamming距离、输入样本、模式样本、类别和序号进行编码.首先,根据样本总体N,计算联想分类器所需的量子位数,再利用量子旋转门和Hadamard门将初态为|0〉的量子位旋转为恰好包含N个基态的均衡叠加态;其次,根据待存储样本的类别和值,将剩余两组初始状态为|0〉的量子位通过可控操作转换为相应的量子基态;最后,基于量子最小搜索的分类方法,计算输入样本与所有存储样本之间的Ha mming距离,再使用固定相位Grover量子搜索算法搜索这些Hamming距离的最小值,最小值对应存储样本的类别即为输入样本的类别,具体的分类结果可通过测量寄存器中的量子态得到.

Reducing the Levels of Sodium, Saturated Animal Fat, and Nitrite in Dry-Cured Pork Meat Products: A Major Challenge

The curing of meat is a conservation technique widely used since ancient times to prolong shelf-life. It consists in exposing meat to a mixture of sodium chloride and nitrate/nitrite. Sodium chloride affects the flavor, texture and shelf-life of meat products. Animal fat mainly affects the flavor and texture, and nitrate and nitrite affect the color and flavor, and give cured meat products their typical aroma. Excessive intake of sodium has been linked to arterial hypertension and increased risk of cardiovascular diseases. Excessive intakes of saturated fatty acids in pork fat, and also of nitrite, have been identified as factors promoting some cancers. There is consequently an increasing consumer demand to reduce these ingredients in processed meat and so develop healthier cured meat products. This paper reviews how and to what extent sodium, animal fat rich in saturated fatty acids, and nitrite contents can be reduced in the production of dry-cured hams and dry-fermented sausages.

Flavor release from traditional dry-cured pork during oral processing

The rate of flavor release in the mouth from traditional dry-cured pork was evaluated in this study.It was hypothesized that a slow steady release of flavor would occur on chewing and hydration.To test this,high salt dry-cured pork was chewed and held in oral cavity without swallowing for 4 different chewing stages(B,NC_(30),C_(30),EC).Saliva and food bolus from 16 healthy subjects were collected during oral processing,and analyzed for saliva flow rate,total saliva protein content,saliva pH,conductivity,saliva and sodium,and taste components.Results show that oral processing behavior and salivary release have important effects on flavor release of dry-cured pork.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)analysis showed that oral processing has a certain effect on the protein composition and concentration in saliva.This study suggests that the interaction between food and saliva that accompanies chewing can lead to significant changes in sensory perception during oral processing.

Dynamic changes in physicochemical property,biogenic amines content and microbial diversity during the fermentation of Sanchuan ham

Sanchuan ham is appreciated in Yunnan Province,China,for its characteristic flavor and taste,while the microbial community structure and biogenic amines content remain unclear during fermentation processes.In this study,we explored the physicochemical property,biogenic amines concentration and microbial diversity of external and internal Sanchuan ham by high-throughput sequencing during the processing of Sanchuan ham.Results showed that the nitrite remained at a stable level of 0.15 mg/kg which was significantly lower than the national health standard safety level of 20 mg/kg.In addition,compared with fresh hams,the content of total free amino acids in ripe Sanchuan ham has grown 14 folds;sour and bitter were the main tastes of Sanchuan ham.Notably,the concentration of cadaverine was the highest of all biogenic amines during the entire fermentation period.At the bacterial phyla level,Firmicutes and Actinobacteria were the two main phyla,while at the genus level,Staphylococcus was a significant strain throughout the whole fermentation.Moreover,the dry stage has a great impact on the succession change of microbial community structure.Simultaneously,the change trends and composition of bacteria in the interior have slight discrepancies with those of the exterior of Sanchuan ham.

基于K-Means聚类的粒子群优化CNN-BiGRU-HAM发动机剩余使用寿命预测方法

飞机在多种工况条件下运行时,发动机退化特征复杂性不断增加,导致发动机剩余寿命预测精度低。针对此问题,提出一种基于聚类分析的端到端剩余寿命(RUL)预测方法。采用K-Means聚类方法对发动机的多种工况和运行条件进行分组;再利用卷积神经网络(CNN)提取反映剩余寿命复杂动态变化的高维特征,将结果输入到双向门控循环单元(BiGRU)中学习特征之间的变化规律,设计并引入了新的混合注意力机制(HAM),充分考虑变量之间的关系,对重要特征信息赋予更大的权重,同时抑制冗余信息的影响;然后进行非线性变换,获得RUL预测结果;最后使用粒子群优化算法对神经网络的超参数进行调优。采用美国航天局NASA研究中心提供的涡轮发动机模拟数据集验证所提网络模型的有效性。结果表明:对于多工况运行条件,所提方法的均方根误差相比于CNN、LSTM、BiLSTM、CNN-LSTM分别降低了49.2%、37.1%、33.6%、24.8%,有效提升了模型的预测精度。

基于双Hamming的NURBS曲线插补算法

针对传统非均匀有理B样条(NURBS)曲线插补中,由于理想插补步长和实际插补步长误差较大引起速度波动的问题,提出一种基于双Hamming的NURBS曲线插补算法。推导差分和导数定义分别变换Hamming方法,得到插补参数的预估、校正公式,再判断校正公式所得插补参数值是否满足速度波动率要求,满足则可继续进行插补,否则利用密勒-牛顿迭代公式对插补参数值进行迭代校正。使用四阶Runge-Kutta方法对初始两插补参数进行求解,并推导插补数值方法关于插补周期的稳定性约束条件。最后对该算法进行仿真,仿真结果表明该算法相较于二阶Taylor、四阶R-K和Adams隐显预估校正算法,平均速度波动率减少30.54%~65.57%,迭代次数减少1.23%~13.12%,证明了该算法在保证较小迭代次数的同时减少了进给速度波动率。

Effects of potassium lactate on sensory attributes,bacterial community succession and biogenic amines formation in Rugao ham

To deepen the understanding in the effect of potassium lactate on the sensory quality and safety of Rugao ham,sensory attributes,physicochemical parameters,total volatile basic nitrogen(TVBN),microorganism community and biogenic amines of Rugao ham manufactured with different potassium lactate levels(0%,0.5%,1%,2%)were investigated;the relationship between microbial community and the formation of TVBN and biogenic amines was further evaluated.With the increase of potassium lactate from 0%to 2%,the increased sensory scores and the decreased total aerobic bacterial count and TVBN were observed;the abundance of Staphylococcus increased,while the content of Halomonas decreased.LDA effect size(LEf Se)and correlations analysis showed that Staphylococcus equorum and Lactobacillus fermentum could be the key species to improve sensory scores and decrease biogenic amines and TVBN.Metabolic pathway analysis further showed that amino acids metabolism and nitrogen metabolism were mainly involved in decreasing TVBN and biogenic amines in the treatment of 2%potassium lactate.

Stability and transepithelial transport of oligopeptide(KRQKYD)with hepatocyte-protective activity from Jinhua ham in human intestinal Caco-2 monolayer cells

The study evaluated the stability of an oligopeptide(Lys-Arg-Gln-Lys-Tyr-Asp,KRQKYD)and its transport mechanism by simulating gastrointestinal digestion and a model of human intestinal Caco-2 monolayer cells in vitro.In this study,the effects of environmental factors(temperature,pH and NaCl concentration)and simulated gastrointestinal digestion on the stability of KRQKYD were evaluated by indicators of the levels of alanine transaminase(ALT),aspartate transaminase(AST)and malondialdehyde(MDA)in an alcoholinduced hepatocyte injury model.The results showed that KRQKYD still maintained satisfactory hepatocyteprotective activity after treatment with different temperatures(20-80℃),pH(3.0-9.0),NaCl concentration(1%-7%)and simulated gastrointestinal digestion,which indicated that KRQKYD showed good stability to environmental factors and simulated gastrointestinal digestion.Furthermore,the intact KRQKYD could be absorbed in a model of Caco-2 monolayer cells with a P_(app)value of(9.70±0.53)×10^(-7)cm/s.Pretreatment with an energy inhibitor(sodium azide),a competitive peptide transporter inhibitor(Gly-Pro)and a transcytosis inhibitor wortmannin did not decrease the level of transepithelial KRQKYD transport,indicating that the transport mechanism of KRQKYD was not associated with energy dependent,vector mediated and endocytosis.The tight junction disruptor cytochalasin D significantly increased the level of transepithelial KRQKYD transport(P<0.05),suggesting that intact KRQKYD was absorbed by paracellular transport.

Variation of microbiological and small molecule metabolite profiles of Nuodeng ham during ripening by high-throughput sequencing and GC-TOF-MS

The internal microbial diversity and small molecular metabolites of Nuodeng ham in different processing years(the first,second and third year sample)were analyzed by high-throughput sequencing technology and gas chromatography-time of flight mass spectrography(GC-TOF-MS)to study the effects of microorganisms and small molecular metabolites on the quality of ham in different processing years.The results showed that the dominant bacteria phyla of Nuodeng ham in different processing years were Proteobacteria and Firmicutes,the dominant fungi phyla were Ascomycota and Basidiomycota,while Staphylococcus and Aspergillus were the dominant bacteria and fungi of Nuodeng ham,respectively.Totally,252 kinds of small molecular metabolites were identified from Nuodeng ham in different processing years,and 12 different metabolites were screened through multivariate statistical analysis.Further metabolic pathway analysis showed that 23 metabolic pathways were related to ham fermentation,of which 8 metabolic pathways had significant effects on ham fermentation(Impact>0.01,P<0.05).The content of L-proline,phenyllactic acid,L-lysine,carnosine,taurine,D-proline,betaine and creatine were significantly positively correlated with the relative abundance of Staphylococcus and Serratia,but negatively correlated with the relative abundance of Halomonas,Aspergillus and Yamadazyma.

基于一种相对Hamming距离的入侵检测方法——RHDID

首先分析了传统入侵检测方法的不足 ,即误用入侵检测方法难于检测新形式的入侵 ,异常入侵检测方法难于建立合理有效的正常行为特征和检测方法 .然后 ,通过对特权进程的系统调用和参数序列的研究 ,提出了一种相对Hamming距离入侵检测方法 (RHDID) .应用RHDID检测入侵不仅能有效降低漏报率和误报率 ,而且使实时入侵检测成为可能 .最后 ,原型系统证实了该方法的可行性 。

基于相对Hamming距离的Web聚类算法

针对Web使用挖掘中聚类结果准确性不高的问题,提出了一种改进的基于相对Hamming距离和类不一致度的聚类算法。该算法首先以Web站点的URL为行、以UserID为列建立关联矩阵,元素值为用户的访问次数;然后,对所建立关联矩阵的列向量或行向量进行相似性度量,获得相似客户群体或相关页面。实验表明,该算法具有较高的准确性。

基于Hamming距离的超立方体网络的寻径算法

本文利用Ｈａｍｍｉｎｇ距离概念，提出两种基于Ｈａｍｍｉｎｇ距离的确定性寻径算法—Ｅ１－ｃｕｂｅｒｏｕｔｉｎｇ和Ｅ２－ｃｕｂｅｒｏｕｔｉｎｇ，分析这两种算法的特点．为了克服确定性寻径算法易出现通道拥挤现象，本文综合上述两种算法，提出一种自适应寻径算法—Ｅ３－ｃｕｂｅｒｏｕｔｉｎｇ．

湖泊营养状态的Hamming贴近度评价法

本文用线性内插构造湖泊富营养化评价参数的隶属函数,在此基础上应用Ham-ming 贴近度评价湖泊的营养状态。该方法用于全国23个湖泊的实例分析,并与其它营养化评价法的评价结果比较表明该方法评价结果合乎实际,隶属函数设计简单,计算方便,具有可比性。

Hamming切趾技术提高体光栅光谱合成功率的研究

体光栅光谱合成技术是获得高功率激光输出的一种有效途径,体光栅衍射旁瓣是影响合成光束数目的主要因素。采用了Hamming切趾技术对体光栅旁瓣进行抑制,建立了Ham-ming切趾体光栅的折射率分布模型,分析了Hamming切趾体光栅的衍射特性,给出了Ham-ming切趾体光栅光谱合成效率公式,分析了切趾光栅对光谱合成效率的影响。计算结果表明:体光栅切趾后有效减小了体光栅对相邻合成光束的衍射损耗,切趾后,在20nm的带宽内,谱合成光束的数目由13束增加为20束,谱合成效率达75.3%,光谱合成功率提高为切趾前的1.5倍。