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.

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.

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.

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）.

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.

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.

Formation mechanisms of reactive carbonyl species from fatty acids in dry-cured fi sh during storage in the presence of free radicals

This study aimed to better understand the changes of fatty acids in dry-cured fish during storage,and to analyze the reactive carbonyl species(RCS)formation mechanism primarily from the standpoint of oxygen-derived free radical reactions interactions.Oleic acid and linoleic acid were the predominant unsaturated fatty acids in dry-cured fish.The content of unsaturated fatty acids in dry-cured fish increased over time at 4℃,while decreased at 25℃.Singlet oxygen,superoxide anion and hydroxyl-alkyl radical levels increased with time,and more free radicals were yielded in the samples held at 25℃.Redundancy analysis revealed that hydroxyl-alkyl radicals had the greatest influence on the oxidation of lipids.Hydroxyl-alkyl radicals and singlet oxygen levels were positively correlated with 4-hydroxy-2-nonenal(HNE),malondialdehyde(MDA),peroxide value and acid value levels,but adversely to 4-hydroxy-2-hexenal(HHE)and fatty acids levels.Moreover,HNE and MDA were both inversely linked with fatty acids contents.It is possible that the intermediates of lipid oxidation undergo oxidation,cleavage and other reactions due to free radical activity,resulting in the generation of aldehyde precursors.These findings help us further characterize the lipid oxidation and RCS formation mechanism in dry-cured fish during storage.

Effects of sugar addition on adipolysis and volatile profiles of dry cured sausage

As sugar play a primary role in food flavor and biochemical reaction during the industrial manufacture of dry cured meat products,we aim to evaluate the function of sugar and how the quality changed with the addition of sugar on dry cured sausage after three months of preservation,and the corresponding effect on acidity value and the total acid value.The roles of sugars’effects on FA hydrolysis and flavor formation are required to be assessed.We selected the addition of sugar with the gradient contents from 3%to 15%,we found that the total acid,acidity value,peroxide value,FA and organic acid were significantly affected.Mono unsaturated fatty acids(MUFA)was the main content of FAs,following by saturated FA and polyunsaturated FA.C18:1n9c was the major FA,following by C16:0 and C18:0.Six kinds of organic acids in dry-cured sausages containing different concentrations of sugar were analyzed by HPLC and the total organic acid reached a maximum of 12.15%by after adding 6%sugar.Acetic acid was 8.06%and lactic acid was 2.56%.This study concludes that sugar is the main factor in flavor formation of dry cured sausage and affects the sausage quality for three months in storage.