Characterization of Volatile Compounds of Dry-Cured Meat Products Using HS-SPME-GC/MS Technique

Analysis of the volatile compounds in Fuliji roast chicken during processing and storage based on GC-IMS

To investigate the flavor changes of Fuliji roast chicken during processing and storage, the volatile organic compounds (VOCs) during processing (fresh, fried, stewed and sterilized) and storage (1 month, 2 months and 4 months) were determined by gas chromatography ion mobility spectrometry (GC-IMS). A total of 47 kinds of VOCs were identified across seven sampling stages, including aldehydes, hydrocarbons, alcohols, ketones, esters, ethers and heterocyclic compounds. More diverse range of aldehydes, alcohols, ketones and esters have been detected compared to acids, ethers and heterocyclic substances. Fingerprints directly reflect the pattern of VOCs at different stages of growth and decay, revealing that frying and stewing are key processes in flavor formation, and that sterilization and storage processes lead to flavor loss in Fuliji roast chicken. Hexanal, nonanal, octanal, 2-heptanone, 3-octanol, 1-octene-3-alcohol, 1-pentanol and ethyl acetate were mainly generated during the frying process. Benzaldehyde, nonanal, octanal, methyl-5-hepten-2-one, 2-methyl-3-heptanone, 1,8-Cineole, linalool, butyl acetate, ethyl propionate, ethyl acetate, coumarin, 2-furfuryl methyl disulfide and 2-pentyl furan were mainly generated during the stewing process. After sterilization, the content of octanal-D, 2-heptanone-D, 2-Methyl-3-heptanone, pentan-1-ol-D decreased, resulting in the reduction of aroma, lemon flavor and oil flavor of Fuliji roast chicken. Seven flavor markers, including hexanal-D, nonanal-M, octanal-M, heptanal-D, acetone, 3-octanol and ethyl acetate-D, were identified in the evolution of the aroma profile of Fuliji roast chicken.

•

GC-IMS profiles of flavor components in poultry product processing line.

•

47 kinds of volatile substances were identified by GC-IMS.

•

Frying and stewing were the key processes of flavor formation.

•

Flavor markers in the evolution of aroma characteristics of Fuliji roast chicken were determined.

Protein Oxidation in Muscle Foods: A Comprehensive Review

Muscle foods and their products are a fundamental part of the human diet. The high protein content found in muscle foods, as well as the high content of essential amino acids, provides an appropriate composition to complete the nutritional requirements of humans. However, due to their special composition, they are susceptible to oxidative degradation. In this sense, proteins are highly susceptible to oxidative reactions. However, in contrast to lipid oxidation, which has been studied in depth for decades, protein oxidation of muscle foods has been investigated much less. Moreover, these reactions have an important influence on the quality of muscle foods, from physico-chemical, techno-functional, and nutritional perspectives. In this regard, the loss of essential nutrients, the impairment of texture, water-holding capacity, color and flavor, and the formation of toxic substances are some of the direct consequences of protein oxidation. The loss of quality for muscle foods results in consumer rejection and substantial levels of economic losses, and thus the control of oxidative processes is of vital importance for the food industry. Nonetheless, the complexity of the reactions involved in protein oxidation and the many different factors that influence these reactions make the mechanisms of protein oxidation difficult to fully understand. Therefore, the present manuscript reviews the fundamental mechanisms of protein oxidation, the most important oxidative reactions, the main factors that influence protein oxidation, and the currently available analytical methods to quantify compounds derived from protein oxidation reactions. Finally, the main effects of protein oxidation on the quality of muscle foods, both from physico-chemical and nutritional points of view, are also discussed.

Fatty Acid Composition and Volatile Profile of longissimus thoracis et lumborum Muscle from Burguete and Jaca Navarra Foals Fattened with Different Finishing Diets

The present study evaluated the effect of breed, Jaca Navarra (JN) vs. Burguete (BU), and finishing diet, conventional concentrate—diet 1 (D1) vs. silage and organic feed—diet 2 (D2), on the fatty acid composition and volatile profile of longissimus thoracis et lumborum muscle from forty-six foals. For this, foals were reared under a semi-extensive system and slaughtered at about 21 months of age. The outcomes showed that breed and finishing regime had a significant (p < 0.05) effect on the lipid and volatile profile of foal meat. In particular, JN foals reported higher polyunsaturated fatty acid contents and better nutritional indices in line with the health guidelines; whereas, BU and D1 groups generated higher amounts of total volatile compounds. However, it was the diet to occupy a central role in this study. Indeed, diet 2, due to its “ingredients” and composition, not only ameliorated the lipid profile of foal meat, but also reduced the generation of volatile compounds associated with lipid oxidation and minimized off-flavors. Thus, this diet could give an added value to the aromatic perception of meat and improve its sensorial acceptability.

An evaluation of biochemical, structural and volatile changes of dry-cured pork using a combined ion mobility spectrometry, hyperspectral and confocal imaging approach

BACKGROUND

Food processing induces various modifications that affect the structure, physical and chemical properties of food products and hence the acceptance of the product by the consumer. In this work, the evolution of volatile components, 2-thiobarbituric acid reactive substances (TBARS), moisture content (MC) and microstructural changes of pork was investigated by hyperspectral (HSI) and confocal imaging (CLSM) techniques in synergy with gas chromatography-ion mobility spectrometry (GC-IMS). Models based on partial least squares regression (PLSR) were developed using the full HSI spectrum variables as well as optimum variables selected through a competitive adaptive reweighted sampling algorithm.

RESULTS

Prediction results for MC and TBARS using multiplicative scatter correction pre-processed spectra models demonstrated greater efficiency and predictability with determination coefficient of prediction of 0.928, 0.930 and root mean square error of prediction of 0.114, 1.002, respectively. Major structural changes were also observed during CLSM imaging, which were greatly pronounced in pork samples oven cooked for 15 and 20 h. These structural changes could be related to the denaturation of the major meat components, which could explain the loss of moisture and the formation of TBARS visualized from the HSI chemical distribution maps. GC-IMS identified 35 volatile components, including hexanal and pentanal, which are also known to have a higher lipid oxidation specificity.

CONCLUSION

The synergistic application of HSI, CLSM and GC-IMS enhanced data mining and interpretation and provided a convenient way for analyzing the chemical, structural and volatile changes occurring in meat during processing. © 2021 Society of Chemical Industry.

Optimization of HS-SPME for GC-MS Analysis and Its Application in Characterization of Volatile Compounds in Sweet Potato

Volatile compounds are the main chemical species determining the characteristic aroma of food. A procedure based on headspace solid-phase microextraction (HP-SPME) coupled to gas chromatography-mass spectrometry (GC-MS) was developed to investigate the volatile compounds of sweet potato. The experimental conditions (fiber coating, incubation temperature and time, extraction time) were optimized for the extraction of volatile compounds from sweet potato. The samples incubated at 80 °C for 30 min and extracted at 80 °C by the fiber with a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) coating for 30 min gave the most effective extraction of the analytes. The optimized method was applied to study the volatile profile of four sweet potato cultivars (Anna, Jieshu95-16, Ayamursaki, and Shuangzai) with different aroma. In total, 68 compounds were identified and the dominants were aldehydes, followed by alcohols, ketones, and terpenes. Significant differences were observed among the volatile profile of four cultivars. Furthermore, each cultivar was characterized by different compounds with typical flavor. The results substantiated that the optimized HS-SPME GC-MS method could provide an efficient and convenient approach to study the flavor characteristics of sweet potato. This is the basis for studying the key aroma-active compounds and selecting odor-rich accessions, which will help in the targeted improvement of sweet potato flavor in breeding.

Use of Meat-Bone Paste to Develop Calcium-Enriched Liver Pâté

The production technology of meat-bone paste and its effect on chemical, mineral and amino acid compositions of liver pâté were studied. The liver was replaced by meat-bone paste in the concentration of 5, 10, 15, 20, and 25% for the production of experimental samples. The compositional analysis of pâté manufactured with meat-bone paste showed that the reformulation did not influence the content of moisture (~56%), fat (~28%), or protein (~11%) while producing a significant increase of ash and a decrease of carbohydrates in comparison with control pâtés. The higher amounts of minerals of bone-meat paste, including calcium (3080 mg/100 g), magnesium (2120 mg/100 g), phosphorous (2564 mg/100 g), and iron (7.30 mg/100 g), explained the higher amount of both ash and these minerals in the reformulated samples compared to the control samples. The total caloric value (~300 kcal/100 g) was also unaffected by the addition of bone-meat paste. The content of both essential and non-essential amino acids decreased with the inclusion of meat-bone paste, although this decrease was lower in essential (6280 mg/100 g in control vs. 5756 mg/100 g in samples with 25% of meat-bone paste) than in non-essential amino acids (6080 mg/100 g in control vs. 3590 mg/100 g in samples with 25% of meat-bone paste). This fact is due to several essential amino acids not showing differences between control and reformulated samples, while in non-essential amino acids, these differences were greater. The results of this study showed that meat-bone paste addition is a good strategy to produce liver pâté enriched in minerals and with minimum influence on the content of the other important nutrients. Therefore, these results can be used for the design of new liver pâté with an increased nutritional significance by using meat industry by-products. According to the balance of minerals, the use of 15% of meat-bone paste to reformulate liver pâté is the best strategy used in the present research. However, additional studies on the stability (during storage), shelf-life, and sensory acceptability of these reformulated pâtés should be carried out.

Objective Measurements Associated with the Preferred Eating Qualities of Fermented Salamis

The development of new food products can be expedited by understanding the physicochemical attributes that are most relevant to consumers. Although many objective analyses are possible, not all are a suitable proxy to serve as quality markers associated with sensory preferences. In this work, we selected nine candidate laboratory assays to use on six commercial salamis, which were also eaten and informally described by a consumer discussion group familiar with China-sourced meat products. Several objective measures were strongly related to the flavour perceptions: (i) texture: instrumental texture values, fat release at oral temperature and fat saturation ratios, (ii) aroma: volatile compounds (e.g., alcohols and esters) associated with microbial fermentation and spices (terpenes and sulphur compounds) and (iii) taste: kokumi taste receptor responses. The fat released at oral temperature was associated with unsaturated fatty acids (r = 0.73). However, there was less explanatory worth for associations between sensory perceptions and proximate composition, water activity, pH or L*, a*, b* colourimetry.

Measurement of Antioxidant Capacity of Meat and Meat Products: Methods and Applications

At present, a wide variety of analytical methods is available to measure antioxidant capacity. However, this great diversity is not reflected in the analysis of meat and meat products, as there are a limited number of studies on determining this parameter in this complex food matrix. Despite this, and due to the interest in antioxidants that prevent oxidation reactions, the identification of antioxidants in meat and meat products is of special importance to the meat industry. For this reason, this review compiled the main antioxidant capacity assays employed in meat and meat products, to date, describing their foundations, and showing both their advantages and limitations. This review also looked at the different applications of antioxidant properties in meat and meat products. In this sense, the suitability of using these methodologies has been demonstrated in different investigations related to these foods.

Influence of the Production System (Intensive vs. Extensive) at Farm Level on Proximate Composition and Volatile Compounds of Portuguese Lamb Meat

Today’s society demands healthy meat with a special emphasis on integrated animal husbandry combined with the concern for animal welfare. In this sense, the raising of lambs in an extensive system has been one of the most common practices, which results in meats with high nutritional value. However, both the production system and the diet play a fundamental role in the chemical composition of the meat, which has a direct impact on the content of volatile compounds. Thus, the aim of this study was to determine the effect of two production systems (intensive and extensive) on the chemical composition and volatile profile of lamb meat. Twenty-eight lambs of the Bordaleira-de-Entre-Douro-e-Minho (BEDM) sheep breed were raised for meat production under the intensive or extensive system and were fed with concentrate and pasture, respectively. All animals were carried out in the muscle longissimus thoracis et lumborum. Results evidenced that all the composition parameters were affected by the production system. Extensively-reared lambs produced meat with the highest fat and protein contents, while these animals had the lowest percentages of moisture and ash. Similarly, the total content of volatile compounds was affected (p < 0.05) by the production system and were higher in the meat of lambs reared extensively. Furthermore, the content of total acids, alcohols, aldehydes, esters, ethers, furans and sulfur compounds as well as most of the individual compounds were also affected (p < 0.05) by the production system, whereas total hydrocarbons and ketones were not affected (p > 0.05). As a general conclusion, the production system had very high influence not only in proximate composition but also in the volatile compounds.

Relationship between volatile organic compounds, free amino acids, and sensory profile of smoked bacon

Flavor is one of the most important characteristics of smoked bacon, strongly affecting its liking by consumers. The smoking process, lipid oxidation and proteolysis contribute to bacon quality through the generation of odors and flavor compounds. In this study, the relationships between free amino acids (FAAs), volatile organic compounds (VOCs) and sensory characteristics of smoked bacon stored for 60 days at 5 °C were investigated. Smoked bacon stored for 30 days was characterized by VOCs associated with the smoking process and lipid oxidation. After 30 days of storage, the bacon samples presented an increase in FAAs produced mainly by proteolysis. Smoked bacon was characterized by the attributes smoky, crunchy, salty, soft and bright. This study demonstrated that VOCs, FAAs and their interactions are responsible for generating sensory attributes and increasing overall liking.

Changes in the chemical and sensory profile of ripened Italian salami following the addition of different microbial starters

In this work, Italian salami were produced using microbial starters (Pediococcus pentosaceus, Lactobacillus sakei, and Staphylococcus xylosus) and compared to a control sample (without starter). Metabolomics in combination with microbiological and sensory analyses were used to investigate the overall quality. Samples were analyzed immediately after stuffing, following 7, 30, and 45 days of ripening. Each microbial starter imposed distinctive metabolomic signatures at the end of ripening. The accumulated discriminant compounds were mainly related to lipid oxidation (including hydroxy- and epoxy derivatives of fatty acids) following the inoculation with L. sakei. However, the inoculation with P. pentosaceus resulted in the accumulation of γ-glutamyl peptides, compounds driving a kokumi-related taste. Noteworthy, our findings supported the involvement of the chemical compounds profiled in the definition of final taste and aroma. This information paves the way towards the definition of more objective and tailored starters-related flavours enhancement approaches in the sector of cured meat.

A comprehensive review of the role of microorganisms on texture change, flavor and biogenic amines formation in fermented meat with their action mechanisms and safety

Meat fermentation ensures its preservation, improved safety and quality. This prominently used traditional process has survived for ages, creating physical, biochemical, and microbial changes, and to significantly affect the functionality, organoleptic property, and nutrition of the fermented products. In some process, the growth of various pathogenic and spoilage microorganisms is inhibited. The production of fermented meat relies on naturally occurring enzymes (in the muscle or the intestinal tract) as well as microbial metabolic activities. In this review, fermented meat types and their health benefits were firstly introduced. This was followed by a description of fermentation conditions vis-à-vis starters, bacterial, yeast and mold cultures, and their role in meat. The review focuses on how microorganisms affect texture change, flavor formation, and biogenic amines (BA) accumulation in fermented meat. In addition, the production conditions and the major biochemical changes in fermented meat products were also introduced to present the best factors influencing the quality of fermented meat. Microorganisms and microbial enzymes in fermented meats were discussed as they could affect organoleptic characteristics of fermented meats. Moreover, safety concerns and prospects for further research of fermented meat were also discussed with emphasis on novel probiotic and starter cultures development; bioinformatics, omics technologies and data modeling to maximize the benefit from fermentation process in meat production.

Recent Development of Gas Sensing Platforms Based on 2D Atomic Crystals

Sensors, capable of detecting trace amounts of gas molecules or volatile organic compounds (VOCs), are in great demand for environmental monitoring, food safety, health diagnostics, and national defense. In the era of the Internet of Things (IoT) and big data, the requirements on gas sensors, in addition to sensitivity and selectivity, have been increasingly placed on sensor simplicity, room temperature operation, ease for integration, and flexibility. The key to meet these requirements is the development of high-performance gas sensing materials. Two-dimensional (2D) atomic crystals, emerged after graphene, have demonstrated a number of attractive properties that are beneficial to gas sensing, such as the versatile and tunable electronic/optoelectronic properties of metal chalcogenides (MCs), the rich surface chemistry and good conductivity of MXenes, and the anisotropic structural and electronic properties of black phosphorus (BP). While most gas sensors based on 2D atomic crystals have been incorporated in the setup of a chemiresistor, field-effect transistor (FET), quartz crystal microbalance (QCM), or optical fiber, their working principles that involve gas adsorption, charge transfer, surface reaction, mass loading, and/or change of the refractive index vary from material to material. Understanding the gas-solid interaction and the subsequent signal transduction pathways is essential not only for improving the performance of existing sensing materials but also for searching new and advanced ones. In this review, we aim to provide an overview of the recent development of gas sensors based on various 2D atomic crystals from both the experimental and theoretical investigations. We will particularly focus on the sensing mechanisms and working principles of the related sensors, as well as approaches to enhance their sensing performances. Finally, we summarize the whole article and provide future perspectives for the development of gas sensors with 2D materials.

Effect of NaCl Partial Replacement by Chloride Salts on Physicochemical Characteristics, Volatile Compounds and Sensorial Properties of Dry-Cured Deer Cecina

The present study aimed to evaluate the effect of NaCl replacement in the physicochemical quality and volatile and sensorial profile of dry-cured deer cecina. Two salt mixtures were used as NaCl substitute: mixture I (30% NaCl-70% KCl) and mixture II (30% NaCl-50% KCl-15% CaCl₂-5% MgCl₂). Regarding the physicochemical parameters, only ash content, pH and L* values were affected by NaCl replacement. However, lipid oxidation was affected by NaCl replacement. The greatest thiobarbituric acid reactive substances (TBARS) values were observed in the control batch (3.28 mg MDA/kg). The partial replacement of NaCl by salt mixtures affected (p < 0.001) Ca, K, Mg, and Na content. The total amounts of free fatty acids and free amino acids were not affected (p > 0.05) by NaCl replacement. Concerning the volatile compounds, control samples presented the highest concentrations of furans (p < 0.01), while samples produced with mixture II had the lowest (p < 0.001) amounts of esters and acids. Our results indicated that all sensory attributes of the attribute map were affected (generalized procrustes analysis (GPA) explained 100% of the total variability among treatments). Considering the results obtained from the sensorial analysis, only mixture II reduced the overall acceptance and preference of consumers. Control attained significantly (p < 0.05) greater scores of acceptance and preference than mixture II despite the higher TBARS content.

Comparative Studies on the Fatty Acid Profile and Volatile Compounds of Fallow Deer and Beef Fermented Sausages without Nitrite Produced with the Addition of Acid Whey

This study aims to improve knowledge on fermented beef and fallow deer sausages and the effect of nitrite elimination and the addition of freeze dried acid whey on the fatty acid profile and volatile compounds. Three different formulations within each of the two product groups, made of beef and fallow deer meat, respectively, were prepared: control sample with sodium nitrite, sample without nitrite, and sample without nitrite and with the addition of freeze-dried acid whey powder (0.7%). After production, the sausages were subjected to analysis including proximate chemical composition, pH and water activity, Thiobarbituric Acid Reactive Substance (TBARS), fatty acid profile, and volatile compound determination. The fermented sausages were characterized by an average pH and water activity in the range of 5.23–5.79 and 0.910–0.918, respectively. Fallow deer sausages were characterized by a higher content of saturated and polyunsaturated fatty acids in comparison to beef sausages. The elimination of nitrite did not significantly affect the amount of volatile compounds in fermented sausages. However, the effect of the freeze-dried acid whey powder addition on the amount of some volatile compounds in uncured sausages was observed, in particular, that derived from bacterial metabolism.

Effect of Different Aging Methods on the Formation of Aroma Volatiles in Beef Strip Loins

This study investigated the effects of different aging methods on the changes in the concentrations of aroma volatiles of beef. One half (n = 15) of the beef strip loins were dry-aged, and the other half were wet-aged, and both aging processes continued for 28 days. The aroma volatiles from dry- and wet-aged samples were analyzed at seven-day intervals (n = 3 for each aging period). As the aging period increased, dry-aged beef showed higher concentrations of volatile compounds than those in wet-aged beef (p < 0.05). Most changes in the concentrations of aroma volatiles of dry-aged beef were associated with propanal, 2-methylbutanal, 2-methylpropanal, 1-butanamine, trimethylamine, 2-methyl-2-propanethiol, and ethyl propanoate, which were mainly produced by lipid oxidation and/or microbial activity (e.g., proteolysis and lipolysis) during the dry aging period. Therefore, we suggest that the differences in aroma between dry- and wet-aged beef could result from increased lipid oxidation and microbial activity in dry-aged beef possibly owing to its ambient exposure to oxygen.

Characterization of flavor volatile compounds in industrial stir-frying mutton sao zi by GC-MS, E-nose, and physicochemical analysis

This study aims to investigate the flavor changes of industrial stir-frying mutton sao zi, a mutton product popular in the northwest of China, at different stir-frying stages. Electronic nose (E-nose) was used to recognize mutton sao zi odors at different processing time points, and the individual volatile compounds were further identified by the solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS). A total of 105 volatile compounds were detected by GC-MS, of which 51 were major volatile compounds. Additionally, GC-MS and E-nose data of the samples were also correlated with the fatty acids, crude composition (moisture, fat, protein), and amino acids. The stir-frying time and temperature may be the critical contributors to different flavors of industrial stir-frying mutton sao zi. The signal intensities of W1S, W1W, W2S, W2W, and W3S sensors positively correlate with protein, fat, and 18 amino acids, but negatively with SFA and moisture. Hence, this study explored the flavor changes of industrial stir-frying mutton sao zi by E-nose and SPME-GC-MS for the first time, providing an insight into the industrial production and flavor control stir-frying machine of stir-frying mutton products with household flavor.

Effects of partial NaCl substitution with high-temperature ripening on proteolysis and volatile compounds during process of Chinese dry-cured lamb ham

The effects of partial NaCl substitution combined with high-temperature ripening on the proteolysis and formation of volatile compounds in dry-cured lamb ham was investigated. Two salt treatments, I (0% KCl + 100% NaCl) and II (25% KCl + 75% NaCl), were considered. Although some studies have analyzed the influences of salt substitution on volatile compounds of dry-cured ham, no studies have evaluated lamb ham produced in China. Intensifying the high-temperature ripening lead to an increase in the formation of flavors generated by the Maillard reaction and Strecker degradation in both treatments, also, had a positive influence on proteolysis index and content of total free amino acids during the ripening stage. The application of 25% KCl did not influence the formation of volatiles during curing stage, however, there were more volatiles came from amino acids degradation in the final products with 25% KCl. Therefore, sodium reduction combined with high-temperature ripening may be an alternative method to manufacture Chinese dry-cured lamb hams.

Use of Turkey Meat Affected by White Striping Myopathy for the Development of Low-Fat Cooked Sausage Enriched with Chitosan

The main objective of this research was the development of a healthy meat product from turkey meat with white striping myopathy. The effect of adding different proportions of chitosan on the qualitative characteristics, sensory acceptance, and stability of cooked sausages during storage was studied. Three treatments were elaborated (control, 1.5% chitosan, and 3% chitosan), stored for 56 days, and characterized in terms of chemical composition, texture profile analysis, drip and pressure loss analysis, and sensory analysis (after processing; day 0). In the different storage periods (0 and 56 days), the pH value, color, thiobarbituric acid reactive substances (TBARS), and volatile compounds were evaluated. The results showed that the moisture content, lipids, proteins, and weight loss decreased (p < 0.05) and the ash content increased (p < 0.05) with the addition of chitosan. Similarly, the values of texture parameters (hardness, cohesiveness, gumminess, and chewiness) were higher in the sausages reformulated with chitosan than in control samples. The addition of chitosan increased the pH and yellowness (b*) values and reduced (p < 0.05) redness (a*) and lightness (L*) values. The b* values (only in reformulated sausages) and pH increased during storage, while a* showed a significant reduction after 56 storage days. Lipid oxidation (TBARS) was kept below the limits of quantification in all samples and both after processing and 56 storage days. However, when quantifying the lipid-derived volatiles, a clear antioxidant activity of chitosan was observed, which limits the release of these compounds, mainly aldehydes (hexanal and nonanal). Finally, the sensory analysis indicated that, although chitosan treatments received the lowest scores for all attributes, the reformulated samples did not differ from control sausages. Therefore, sausage containing chitosan may represent an interesting alternative for adding value to turkey meats affected by white striping myopathy and, at the same time, develop into a healthy and functional meat product increasing the proportion of fibers in one’s diet.

Polyunsaturated fatty acid, volatile and sensory profiles of beef from steers fed citrus pulp or grape pomace

The present study compared the effects of feeding dried grape pomace (DGP) or citrus pulp (DCP) at 150 g/kg dry matter compared to a control diet on major polyunsaturated fatty acids (PUFA), volatile and sensory profiles of beef. Feeding DGP or DCP diets to Angus steers for 90 d increased the proportions of C18:2n-6, C20:4n-6, C18:3n-3, total conjugated linoleic acid (CLA), n-3 and n-6 PUFA in muscle. Control-fed beef had greater concentrations of C18:1n-9, total aldehydes, ketones, and alcohols compared to DCP and DGP. Feeding DGP and DCP diets produced less tender beef than control. Overall, finishing steers on diets containing DGP or DCP compared to control increased proportions of total CLA, n-3 and n-6 PUFA, and reduced concentrations of aldehydes, ketones, and alcohols, but did not affect beef sensory attributes except for a slight reduction in tenderness.

How Volatile Compounds, Oxidative Profile and Sensory Evaluation Can Change with Vacuum Aging in Donkey Meat

Simple Summary

Aging in donkey meat was never investigated. It represents an important process, because it leads the muscle to become meat. There are many ways to age meat, and vacuum aging is one of these. The present paper characterised donkey meat Volatile Organic Compounds (VOCs) production during 14 vacuum aging days, its oxidative status and the consequent sensory evaluation. Lipid oxidative processes are delayed, but some protein oxidative processes happen, influencing VOCs production and sensory evaluation.

Abstract

This study aims to improve knowledge on donkey meat and the vacuum aging effect on the Volatile Organic Compounds (VOCs), oxidative profile and status and the sensory characteristics. Ten 18-month old Martina Franca donkeys’ male foals were involved in the trial. Longissimus thoracis (LT) muscle was extracted from each left half carcass, between the fourth and the ninth rib. Each muscle was divided into five sections, vacuum packaged, stored at 2 °C, and randomly assigned to one of the different aging time (1, 3, 6, 9, and 14 days of aging). Volatile compounds, oxidation parameters, and antioxidant enzymes were analysed, and a sensory test was performed. A nested one-way analysis of variance (ANOVA) was performed for aging time as an independent variable. Significance was set at p < 0.05. Aldehydes are the most produced VOCs, but no changes were observed during vacuum aging (p > 0.05). Nitrogen compounds increased during aging (p < 0.01). TBARs and hydroperoxides did not change during the storage, whereas the protein carbonyls increased (p < 0.05). Vacuum aging slowed down lipid oxidation and put in evidence the presence of protein oxidation and degradation, influencing the VOCs productions and sensory evaluation.

Low-sodium dry-cured rabbit leg: A novel meat product with healthier properties

Dry-cured rabbit legs were produced with a 50% reduction or replacement of NaCl by KCl and with the addition of monosodium glutamate (MG). The effect of this reformulation on technological, nutritional, and sensory characteristics was evaluated. The sodium reformulation did not show a great impact on Aw, pH, weight loss, and volatile profile of the samples. The samples presented high protein (31.5 to 36.1%) and low fat contents (3.2 to 5.7%). In addition, all essential amino acids presented an amino acid score greater than 1.0. The reformulated samples showed a sodium reduction of 46.2% while the addition of KCl to the formulations provided a healthy Na/K ratio. Oleic acid was the major fatty acid (FA) (31.3% of total FA) and healthy lipid indexes were observed for all samples. Finally, the addition of MG was effective to compensate for the sensory defects caused by sodium reformulation.

Application of Proteomic Technologies to Assess the Quality of Raw Pork and Pork Products: An Overview from Farm-To-Fork

The quality assurance of pork meat and products includes the study of factors prior to slaughter such as handling practices, diet and castration, and others during the post-mortem period such as aging, storage, and cooking. The development over the last two decades of high-throughput techniques such as proteomics offer great opportunities to examine the molecular mechanisms and study a priori the proteins in the living pigs and main post-mortem changes and post-translational modifications during the conversion of the muscle into the meat. When the most traditional crossbreeding and rearing strategies to improve pork quality were assessed, the main findings indicate that metabolic pathways early post-mortem were affected. Among the factors, it is well documented that pre-slaughter stress provokes substantial changes in the pork proteome that led to defective meat, and consequently, novel protein biomarkers should be identified and validated. Additionally, modifications in pork proteins had a strong effect on the sensory attributes due to the impact of processing, either physical or chemical. Maillard compounds and protein oxidation should be monitored in order to control proteolysis and volatile compounds. Beyond this, the search of bioactive peptides is becoming a paramount goal of the food and nutraceutical industry. In this regard, peptidomics is a major tool to identify and quantify these peptides with beneficial effects for human health.

Inclusion of Healthy Oils for Improving the Nutritional Characteristics of Dry-Fermented Deer Sausage

The influence of partial replacement of animal fat by healthy oils on composition, physicochemical, volatile, and sensory properties of dry-fermented deer sausage was evaluated. Four different batches were manufactured: the control was formulated with animal fat (18.2%), while in the reformulated batches the 50% of animal fat was substituted by olive, canola, and soy oil emulsions immobilized in Prosella gel. The reformulation resulted in a decrease of moisture and fat contents and an increase of protein and ash amount. Moreover, reformulated sausages were harder, darker, and had higher pH values. This fact is related to the lower moisture content in these samples. As expected, the fatty acid composition was changed by the reformulation. The use of soy and canola oils increased polyunsaturated fatty acids and omega-3 content and decreased n-6/n-3 ratio and saturated fatty acids. Thus, the use of these two oils presented the best nutritional benefits. The changes observed in the fatty acids reflected the fatty acid composition of the oils employed in the emulsions. Regarding volatile compounds (VOC), the replacement of animal fat by healthy emulsion gels increased the content of both total VOC and most of individual VOC. However, the lipid-derived VOC did not show this trend. Generally speaking, the control samples presented similar or higher VOC derived from lipid oxidation processes, which could be related to the natural antioxidant compounds present in the vegetable oils. Finally, all reformulated sausages presented higher consumer acceptability than control samples. In fact, the sausage reformulated with soy oil emulsion gel was the most preferred. Thus, as a general conclusion, the reformulation of deer sausages with soy emulsion gel improves both composition and sensory quality of the final product, which could be an excellent strategy to the elaboration of healthy fermented sausages.

Natural Antioxidants from Seeds and Their Application in Meat Products

The use of synthetic antioxidants in the food industry has raised important questions about the effects of prolonged consumption on human health. On top of that, the consumption of meat products has been changing due to the awareness generated by health-related organizations. In this sense, exploring strategies to develop and produce healthier meat products has become a paramount concern. Several studies explored the composition of several seeds to characterize and explore the compounds with antioxidant activity, which are mainly composed of polyphenols. The use of antioxidant extracts in meat products has shown important results to delay the oxidative reactions in meat products derived from the processing and storage of meat products. Moreover, these extracts can also replace synthetic antioxidants and preserve the quality of meat products. Therefore, the aims of this review are first, to present the sources and compounds with antioxidant activity in seeds, and second, to discuss their protective effect against oxidative reactions in meat products.

Effects of sous vide vs grilling methods on lamb meat colour and lipid stability during cooking and heated display

The present study compared the effect of grilling (150 °C until 72 °C core temperature) and sous-vide (SV) cooking (75 °C for 35 min in a water bath under vacuum) on lamb patties immediately after cooking and after 4 h display at 65 °C. Both methods produced patties with similar (P > 0.05) weight loss, and moisture and fat contents. SV-cooking prevented (P < 0.05) the formation of thiobarbituric acid reactive substances (TBARS) and oxysterols compared to grilled patties, which showed a larger proportion of highly peroxidisable polyunsaturated fatty acids. Heated display induced dehydration, surface darkening and a reduction in the hexanal/3-methylbutanal ratio, suggesting the progression of Maillard reactions. Moreover, TBARS and some lipid oxidation-derived volatiles increased (P < 0.001), while cooked-meat aroma compounds were reduced (P < 0.001). SV-cooking inhibited (P < 0.05) the formation of malondialdehyde, and 7α- and 7β-hydroxycholesterol, and lowered the cholesterol oxidation ratio during heated display. Overall, SV-cooking may be considered a healthier way of cooking when lamb meat is to be kept warm for considerable periods before consumption.

Volatile Organic Compounds, Oxidative and Sensory Patterns of Vacuum Aged Foal Meat

The study aimed to evaluate the effect of 14-day vacuum aging on the volatile compounds (VOC) profile, oxidative profile, antioxidant enzymes activity, and sensory evaluation in the Longissimusthoracis muscle of foal meat under vacuum aging. Longissimusthoracis (LT) was sampled in 20 mm thick slices, vacuum packed, and stored at 4 °C. Samples were randomly assigned to different aging times (1, 6, 9, 14 days after slaughtering). VOCs, thiobarbituric acid reactive substances (TBARs), hydroperoxides, carbonyl proteins, superoxide dismutase, catalase, and glutathione peroxidase were analyzed, and a sensory test was performed. A nested one-way analysis of variance (ANOVA) was performed for aging time as an independent variable. Significance was set at p < 0.05. The main VOCs originating from cooked steaks were aldehydes, (from 47.18% to 58.81% of the total volatile compounds), followed by hydrocarbons (from 9.32% and 31.99%). TBARs and hydroperoxides did not show variations due to aging (p > 0.05), instead, protein carbonyls showed higher values at the 14th day (p < 0.01). Catalase, superoxide dismutase, and glutathione peroxidase showed increasing values during aging time (p < 0.01). Vacuum aging slowed down lipid oxidation, and protein oxidation was shown to be present. However, the best vacuum aging duration is in the range of 6-9 days from slaughtering, with an improvement of sensory evaluation.

Turmeric (Curcuma longa L.) extract on oxidative stability, physicochemical and sensory properties of fresh lamb sausage with fat replacement by tiger nut (Cyperus esculentus L.) oil

This study aimed to evaluate the effect of turmeric extract as natural antioxidant on modified atmosphere-packaged fresh lamb sausages with fat replacement during storage (2 °C). Five treatments were prepared: control without antioxidant (CONT); with 500 mg/kg sodium erythorbate (E500); and three batches with 250, 500 or 750 mg/kg turmeric extract (T250, T500 and T750), respectively. The proximate composition, pH, color, texture, oxidative stability, sensorial analysis, free fatty acids and volatile compounds of sausages were analyzed. Turmeric extract improved the antioxidant capacity of lamb sausages and also slowed lipid oxidation and the generation of related volatile compounds. Moreover, physic-chemical parameters of lamb sausages were not greatly influenced by turmeric addition and concentration, except for yellow color. All samples were considered acceptable by consumers. These findings showed that turmeric extract is effective against lipid oxidation and could be a good strategy to enhance the shelf life of lamb sausage.

Influence of the Inclusion of Chestnut (Castanea sativa Miller) in the Finishing Diet and Cooking Technique on the Physicochemical Parameters and Volatile Profile of Biceps femoris Muscle

The aim of this study was to evaluate the influence of the diet (chestnut vs. commercial feed) and cooking techniques (roasting, grilling, frying and microwaving) on the quality of the Biceps femoris muscle of the Celta pig breed. Chemical composition, physicochemical parameters, oxidative stability and volatile profile were analysed. Overall, the inclusion of chestnuts did not affect the chemical composition, except for intramuscular fat content, which was higher in chestnut-fed pigs. The colour and shear force of cooked Biceps femoris were not affected by the finishing diet. However, a significant increase in cooking losses and thiobarbituric acid reactive substances (TBARS) value was found with the chestnuts included in the diet. In addition, the inclusion of chestnuts also modified some volatile compound that could be associated with the diet, such as furan, 2-pentyl. On the other hand, the cooking method significantly affected chemical composition (moisture, fat, protein and ash content), colour parameters, cooking loss, TBARS and volatile profile, whereas the shear force was not affected. Concretely, fried and microwave were the techniques that led to a greater presence of intramuscular fat. In addition, the frying method also showed the highest a* value, whereas the microwaved technique displayed the highest cooking loss. Regarding lipid oxidation, the fried method displayed the lower TBARS and hexanal content. On the other hand, the major volatile compounds were aldehydes in all cooking methods except for the frying technique in chestnut samples. Finally, method-frying displayed the lowest amount of total volatiles compounds, unlike grilling.

Sensory Changes and Listeria monocytogenes Behavior in Sliced Cured Pork Loins during Extended Storage

Cured pork loins are sausages with a production tradition in several regions worldwide. They are made from one of the noblest cuts of pork, and for this reason cured loins are one of the most expensive pork meat products. Establishing the correct shelf life allows products to be accepted by the consumer, and to avoid the costs associated with shorter shelf lives. The aim of this study is: (1) to establish proper shelf life by evaluating the willingness of participants to consume and the sensory modifications that occur during prolonged storage via Check All That Apply (CATA) questions; and (2) to study the behavior of Listeria monocytogenes through a microbial challenge test. Sliced cured pork loins can be stored at 6 ± 1 °C for 105 days while maintaining a consumer acceptance of more than 75%. The freshness loss was associated mainly with a decrease in aromatic notes (particularly the smoke and cured aroma), and with the appearance of spoiled characteristics, specifically a sour/vinegar aroma and acidic taste that were detected by a reduced proportion of participants. The freshness evaluation was positively influenced by the typical characteristics of cured products, such as color and a garlic and wine aroma. Sour/vinegar aroma and acidic taste were the attributes most associated with higher freshness penalization. During the period of the test, Listeria monocytogenes inoculated onto the cured loin slices did not grow.

Consumer Acceptance and Quality Parameters of the Commercial Olive Oils Manufactured with Cultivars Grown in Galicia (NW Spain)

Mansa and Brava are olive autochthonous cultivars from Galicia, a new olive-growing zone from NW Spanish, from which high-quality extra virgin olive oils (EVOOs) are obtained. The oils obtained as by co-crushing Mansa and Brava olives in different proportions as by blending with others olives cultivars have different composition that influence in their sensory quality. The consumer acceptance of commercial oils elaborated with Local Galician cultivars was evaluated and a quality-mapping of olive oils was created. It was found that the both Local oils had good physical-chemical quality parameters. From sensory analysis viewpoint, Local-MB oils presented the highest intensity values for color, odor, taste, and flavor, and the consumers had a higher acceptance and preference by Picual, Local-MBPA (60% Mansa and Brava, 25% Picual, and 15% Arbequina and Local-MB (60% Mansa and 40% Brava) oils. A quality-mapping of olive oils indicate that attributes better scored from the consumer are high intensity for color, odor, taste and flavor, and pungent and floral series, and bitter is rejected by them.

Analysis of Volatile Components in Different Ophiocordyceps sinensis and Insect Host Products

The artificial production of Ophiocordyceps sinensis mycelia and fruiting bodies and the Chinese cordyceps has been established. However, the volatile components from these O. sinensis products are not fully identified. An efficient, convenient, and widely used approach based on headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography and quadrupole time-of-flight mass spectrometry (GC×GC-QTOFMS) was developed for the extraction and the analysis of volatile compounds from three categories of 16 products, including O. sinensis fungus, Thitarodes hosts of O. sinensis, and the Chinese cordyceps. A total of 120 volatile components including 36 alkanes, 25 terpenes, 17 aromatic hydrocarbons, 10 ketones, 5 olefines, 5 alcohols, 3 phenols, and 19 other compounds were identified. The contents of these components varied greatly among the products but alkanes, especially 2,5,6-trimethyldecane, 2,3-dimethylundecane and 2,2,4,4-tetramethyloctane, are the dominant compounds in general. Three categories of volatile compounds were confirmed by partial least squares-discriminant analysis (PLS-DA). This study provided an ideal method for characterizing and distinguishing different O. sinensis and insect hosts-based products.

Characterization and differentiation of boiled pork from Tibetan, Sanmenxia and Duroc × (Landrac × Yorkshire) pigs by volatiles profiling and chemometrics analysis

To characterize and differentiate boiled pork from three different pig breeds (Tibetan, Sanmenxia and Duroc × (Landrace × Yorkshire)), the volatile compounds in each were analysed by gas chromatography-olfactometry-mass spectrometry (GC-MS/O) and electronic nose (E-nose) combined with chemometrics analysis. In total, 61 volatile compounds were identified, among which 25 compounds were selected as odour-active compounds in boiled pork. Moreover, seven odour-active compounds (hexanal, nonanal, 1-octen-3-ol, dimethyl disulphide, heptanal, 2-pentylfuran and 2-ethylfuran) were the main contributors to the integral flavour of boiled pork due to their higher odour activity values (OAVs) ranging from 17.3 to 524.2. The odour-active compounds were examined by principal component analysis (PCA), agglomerative hierarchical clustering (AHC) and partial least squares-discriminant analysis (PLS-DA). The results showed that boiled pork from the three pig breeds could be clearly distinguished, and twelve odour-active compounds, including (E,E)-2,4-decadienal, ethyl hexanoate, dimethyl disulphide, hexanal, 2-acetylthiazole, (E)-2-nonenal, 1-octen-3-ol, (E,E)-2,4-nonadienal, heptanal, (E)-2-octen-1-ol, styrene and (E)-2-octenal, were determined as potential flavour markers for discrimination. This study indicated that GC-MS/O and E-nose with chemometrics analysis are feasible methods to characterize and discriminate boiled pork from three pig breeds.

Inclusion of Ethanol Extract of Mesquite Leaves to Enhance the Oxidative Stability of Pork Patties

The lipid oxidation (LOX) of pork meat has been associated with loss of quality and shorter shelf life. Consequently, synthetic antioxidants have been used to reduce this process, but their use has shown potential health risks. Thus, the use of natural ingredients has been suggested as a strategy to prevent LOX. This study aimed to assess the oxidative stability of pork patties treated with ethanol extract of mesquite leaf (EEML) during storage. Furthermore, the polyphenol composition (TPC, total phenolic, TFC, total flavonoid) and antioxidant activity (antiradical and reducing power activity) of EEML were also evaluated. For this study, five treatments (CN (control), without antioxidant; Asc, ascorbic acid 0.02%; BHT, butylated hydroxytoluene 0.02%; EEML1, 0.05%; and EEML2, 0.1%) of pork patties were applied. Patty samples were stored at 4 °C, and physicochemical parameters, lipid oxidation, total antioxidant capacity of the meat, and sensory analysis were evaluated at 0, 3, 7, and 10 days of storage. EEML presented high values of TPC (278.5 mg gallic acid equivalent (GAE)/g) and TFC (226.8 mg rutin equivalents (RE)/g) levels. The addition of EEML did not modify the chemical composition of the pork patties. On the other hand, colour parameters were affected by the inclusion of EEML in pork patties, presenting the lowest a* in the CN group compared to the other groups after 10 days storage. Lipid oxidation increased during the whole period, showing the lowest (P < 0.05) conjugated dienes and thiobarbituric acid reactive substances (TBARS) values (40% and 90% of inhibition, respectively) compared to the CN group. Regarding sensory analysis, there were no significant differences in colour, appearance, odour, flavour, juiciness, fat sensation, and firmness of the cooked pork patties among treatments. These results suggest that EEML has great potential as a natural antioxidant for meat products.