Functional fermented meat products with probiotics-A review.

Fermentation has been an important strategy in the preservation of foods. The use of starter cultures with probiotic activity has gained the attention of researchers to produce functional fermented meat products. This review aims to overview the main strengths, weakness, opportunities and threats of fermented meat products with probiotics. Fermented meat products can be considered as a relevant matrix for the delivery of probiotics with potential health benefits. Moreover, fermented meat products produced by traditional methods are sources of probiotics that can be explored in the production of functional meat products. However, some barriers are limit the progression with these products: the complex selection process to obtain new and tailored probiotic strains, the current perception of healthiness associated with meat and meat products, and the limited application of probiotic to fermented sausages. Promising opportunities to improve the value of functional fermented meat products have been developed by exploring new meat products as functional fermented foods, improving the protection of probiotics with microencapsulation and improving the quality of meat product (reducing nitrate and nitrate salts, adding dietary fibre, and exploring the inherent antioxidant and cardioprotective activity of meat products). Attention to potential threats is also indicated such as the unclear future changes in meat and meat products consumption due to changes in consumer preferences and the presence of competitors (dairy, fruit and vegetable-based products, for instance) in more advanced stages of development and commercialization. SIGNIFICANCE AND IMPACT OF STUDY: This review provides an overview of the Strengths, Weakness, Opportunities and Threats related to the development of functional fermented meat products with probiotics. Internal and external factors that explain the current scenario and strategies to advance the production are highlighted.

A DFT Study of the Reaction of Acrylamide with L-Cysteine and L-Glutathione.

Thermal processing of certain foods implies the formation of acrylamide, which has been proven to provoke adverse effects on human health. Thus, several strategies to mitigate it have been developed. One of them could be the application of organosulfur compounds obtained from natural sources to react with the acrylamide, forming non-toxic adducts. A DFT study of the acrylamide reaction with the organosulfur model compounds L-cysteine and L-glutathione by Michael addition and a free radical pathway complemented by a kinetic study of these model molecules has been applied. The kinetic evaluation results demonstrate that the L-glutathione reaction exhibited a higher rate constant than the other studied compound.

Ternary Quantum Dots in Chemical Analysis. Synthesis and Detection Mechanisms.

Ternary quantum dots (QDs) are novel nanomaterials that can be used in chemical analysis due their unique physicochemical and spectroscopic properties. These properties are size-dependent and can be adjusted in the synthetic protocol modifying the reaction medium, time, source of heat, and the ligand used for stabilization. In the last decade, several spectroscopic methods have been developed for the analysis of organic and inorganic analytes in biological, drug, environmental, and food samples, in which different sensing schemes have been applied using ternary quantum dots. This review addresses the different synthetic approaches of ternary quantum dots, the sensing mechanisms involved in the analyte detection, and the predominant areas in which these nanomaterials are used.

Influence of Potato Crisps Processing Parameters on Acrylamide Formation and Bioaccesibility.

A fractional factorial design was used to evaluate the effects of temperature, frying time, blanching treatment and the thickness of potato slices on acrylamide content in crisps. The design was used on freshly harvested and four-month stored potatoes. The critical factors found were temperature and frying time, and the interaction between blanching treatment and slice thickness. Once frying conditions were selected, an acrylamide content of 725 and 1030 mg kg-1 was found for non-stored and 4-month stored tubers, with adequate textural parameters in both cases. The difference in concentration is related to storage conditions, which must be controlled in order to control acrylamide levels. Bioaccesibility studies demonstrated that acrylamide concentration remained at 70%, and reductions took place mainly at the intestinal phase, as a result of reaction with nucleophilic compounds.

New Poly(Ionic Liquid) Based Fiber for Determination of Oxytetracycline in Milk Samples by Application of SPME-CE Technique.

In this work, a procedure using solid phase microextraction in combination with capillary electrophoresis was developed for the determination of oxytetracycline in milk samples. The method involves the synthesis of poly(1-allyl-3-methyl imidazolium) chloride film on a stainless-steel bar via electropolymerization and its use as an adsorbent for oxytetracycline (OT) by an ionic exchange mechanism. The coated fiber is then immersed in milk samples for retention of oxytetracycline residues, followed by elution, drying, and reconstitution before analysis with capillary electrophoresis. The proposed method achieves a limit of detection of 70 µg L⁻¹ with adequate precision and uncertainty, making this methodology appropriate for the determination of OT in milk samples. The method was applied to the pre-concentration and quantification of oxytetracycline in ten commercial milk samples. Two tested samples were positive for the presence of oxytetracycline but the concentration was below the maximum residue limit according to the international normative standard. The proposed methodology was evaluated according to the Eco-Scale approach, and the total score of 51 indicated that the methodology proposed is both green and acceptable despite the multi-stage character. SPME-CE methodology allows us to perform the sample pre-treatment and determination of OT in an effective and greener way, decreasing the number of steps during the analysis and the generation of waste.

Algae as a potential source of protein meat alternatives.

With the rise of plant-based meat alternatives, there is a growing need for sustainable and nutritious sources of protein. Alga is a rich protein source, and initial studies show that it can be a good component in developing protein meat alternatives. However, there are certain limitations in their use as the need for efficient and optimal technical process in large-scale protein extraction and purification, as well as overcoming certain negative effects such as potentially harmful compounds, allergenicity issues, or sensorial affections, especially in color but also in textural and flavor characteristics. This review offers a vision of the fledgling research about using alga protein in the development of meat alternatives or supplementing meat products.

Effect of Partial Meat Replacement by Hibiscus sabdariffa By-Product and Pleurotus djamor Powder on the Quality of Beef Patties.

The effects of Hibiscus sabdariffa (roselle; Hs) by-product (2-5%) and Pleurotus djamor (pink oyster; Pd) powder (5-7.5%) as meat replacers on the physicochemical and sensorial properties of beef patties were analyzed. The addition of these non-meat ingredients significantly decreased moisture and increased fiber content, and did not affect the protein level of the product. The antioxidant effect of the roselle by-product was limited, while Pleurotus djamor favored the oxidation processes. The samples supplemented with roselle by-product and mushroom powder presented significantly lower microbial counts (total viable counts, enterobacteria, and Pseudomonas) than control, but texture and sensorial parameters were significantly affected. The patties darkened due to the presence of the Hibiscus by-product, while the color of the samples containing 5% Pleurotus djamor was hardly modified. These samples, together with the control samples, were the most sensorially appreciated. The addition of these ingredients provoked a decrease in texture parameters, being less pronounced in the samples with only 2% of roselle by-product. In spite of the good antimicrobial and antioxidant properties of Hibiscus by-products, its inclusion in meat should be moderate (2-2.5%) to avoid consumer rejection when Pleurotus djamor is also included in the formulation.

Determination of quinolones in milk samples using a combination of magnetic solid-phase extraction and capillary electrophoresis.

A magnetic solid-phase extraction (MSPE) method combined with capillary electrophoresis for the simultaneous determination of seven quinolones (QNs) (danofloxacin, ciprofloxacin, marbofloxacin, enrofloxacin, difloxacin, oxolinic acid, and flumequine), using (S)-(+)-6-methoxy-α-methyl-2-naphthaleneacetic acid as internal standard, in milk samples was developed. The variables involved in the preconcentration magnetic procedure were: the composition of the magnetic support composition, the sample pH, and the weight of magnetic adsorbent used. The variables were optimized using a simplex-lattice design. Different magnetite covered with octyl-phenyl silica adsorbents were synthesized by varying the molar ratio of phenyltrimethylsilane and octyltrimethoxysilane; the solids were evaluated for QN preconcentration. Under optimal conditions, a linear range was obtained from 27 to 1000 µg L(-1) with limits of detection ranging from 9 to 12 µg L(-1) for the seven QNs. The absolute recoveries of the seven QNs at three different spiked levels (40, 150, and 400 µg L(-1) ) ranged from 74% to 98% with a relative standard deviation less than 10% in all cases. The proposed method was applied to analyze 20 whole milk samples of different brands. All samples were positive for the presence of QN residues; in some cases, extract dilution was required. The concentrations found are in the range from 31.1 to 5047.3 µg L(-1) . Marbofloxacin was the most frequently found. The method proposed offers advantages in terms of simplicity, sensitivity, efficiency, cost, and analysis time making it an alternative for the analysis of QNs in whole milk samples.

Fluorescence assay for acrylamide determination in fried products based on AgInS2/ZnS quantum dots.

AgInS2/ZnS quantum dots were synthesized via solvothermal aqueous phase method using 3-mercaptopropionic acid as the stabilizer. AgInS2/ZnS quantum dots were employed for acrylamide sensing under two strategies: (1) quenching of the fluorescence signal by the synthesis of polyacrylamide under UV light and (2) use of 2-naphthalenethiol for quenching of the fluorescence signal of quantum dots followed by a recovery of the signal after the addition of acrylamide. Both methodologies display adequate limits of detection, 15.6 and 4.8 µg L-1, respectively. However, the 2-napthalenethiol based method exhibited better precision and selectivity compared to the other methodology. Both methodologies were applied for acrylamide detection in fried snack products and acceptable accuracy was obtained using 2-napthalenethiol method.

Natural Antimicrobials: A Clean Label Strategy to Improve the Shelf Life and Safety of Reformulated Meat Products.

Meat is a nutrient-rich matrix for human consumption. However, it is also a suitable environment for the proliferation of both spoilage and pathogenic microorganisms. The growing demand to develop healthy and nutritious meat products with low fat, low salt and reduced additives and achieving sanitary qualities has led to the replacement of the use of synthetic preservatives with natural-origin compounds. However, the reformulation process that reduces the content of several important ingredients (salt, curing salts, etc.), which inhibit the growth of multiple microorganisms, greatly compromises the stability and safety of meat products, thus posing a great risk to consumer health. To avoid this potential growth of spoiling and/or pathogenic microorganisms, numerous molecules, including organic acids and their salts; plant-derived compounds, such as extracts or essential oils; bacteriocins; and edible coatings are being investigated for their antimicrobial activity. This review presents some important compounds that have great potential to be used as natural antimicrobials in reformulated meat products.

Reduction of Salt and Fat in Frankfurter Sausages by Addition of Agaricus bisporus and Pleurotus ostreatus Flour.

The reduction of fat and salt and the incorporation of fiber-rich compounds in frankfurters is a trend to improve their nutritional profile. The objective of this study was to evaluate the partial replacement of 30 and 50% of pork backfat and 50% of salt by adding edible mushroom flour (2.5 and 5%) from Agaricus bisporus (Ab) and Pleurotus ostreatus (Po) on physicochemical, microbiological and sensory properties of frankfurters sausages during cold storage. The addition of flours increased the moisture, and the dietary fiber contents in frankfurters, keeping the amino acid profile. Lipid oxidation remained under acceptable values despite not antioxidant effect was observed by mushrooms flours. Only spore-forming bacteria were found during cold storage. Color and texture was modified by addition of mushroom, being the Ab samples darker, while Po flour addition resulted in softer and less cohesive sausages. Although lower color, flavor, and taste scores were given to the mushroom samples than the control, they ranked in the acceptable level confirming that the inclusion of 2.5 and 5% of Ab and Po flours in fat- and salt-reduced frankfurter sausages resulted a feasible strategy to enhance the nutritional profile these products.

Effectiveness of combined preservation methods to extend the shelf life of Morcilla de Burgos.

Morcilla de Burgos is the most famous blood sausage in Spain. However, while producers are interested in extending its shelf life, the consumer is increasingly demanding more natural food. This situation has led to the current search for new and mild preservation technologies. Two batches of four different products: control without any treatment, control with organic acid salts (CnOAS; a 3% mixture of potassium/sodium l-lactate), control with high hydrostatic pressure processing (CnHPP; 600MPa-10min), and a combination of both treatments (OAS+HPP), were carried out to evaluate any synergistic effect that occurs when combining OAS and HPP, and the influence of different preservative treatments on the spoilage bacterial population and their evolution. HPP (with or without addition of OAS) can be considered the most suitable method for preserving morcilla de Burgos as it does not produce negative changes in sensory attributes. No clear selective effect of different treatments on the composition of the spoilage bacteria was seen and similar spoilage patterns were observed independently of the preservation treatment used.

A theoretical and experimental approach to evaluate zein-calcium interaction in nixtamalization process.

The possible interactions between α-zein and Ca2+ in nixtamalization process were analyzed from a multidisciplinary approach, considering the effect of these interactions on the thermal properties of the nixtamalized flour. SDS-PAGE under reducing and non-reducing conditions did not reveal differences between patterns of zeins from nixtamalized and control samples. However, analysis from affinity capillary electrophoresis indicated an increment in protein volume when calcium is added to zein extracted from nixtamalized flour. In addition, the binding constant for the zein-calcium interaction was calculated indicating a higher affinity for calcium by zein from nixtamalized samples. Molecular dynamics simulations indicated that the interaction α-zein-Ca2+ through C-ter was more favorable than Glu48. However, in excess of Ca2+ ions, each site could bind one calcium atom at the same time, confirming that aggregation of α-zein through calcium bridges is possible, expanding the technological applications of this protein.

Active packaging films with natural antioxidants to be used in meat industry: A review.

Spoilage of meat products during processing, distribution and exposure in the markets have an important negative impact on meat industry from an economic point of view. Two of the main problems of meat and products during processing and subsequent storage are lipid oxidation and deterioration due to microorganism growth. In this context, several packaging alternatives have been developed by meat industry in order to limit these losses and to extend the meat products´ shelf life. Over the last years, the use of active packaging has been proposed as an alternative to traditional packaging. The principle of active packaging, particularly antioxidant active packaging, consists of including active agents in the packaging which interact with meat and/or its environment, either by trapping pro-oxidant compounds or by releasing antioxidant compounds in order to delay degradation due to lipid oxidation. Therefore, the use of active packaging is presented as a future option to solve the problems derived from oxidative deterioration of meat and meat products. However, its use will depend on the costs involved in the development of this active packaging. Therefore, this review will give an overview about the use of active packaging and natural antioxidants, the active film development techniques, as well as the use of biopolymers as substitutes for synthetic polymers and their direct application in the meat industry.

Diversity of Weissella viridescens strains associated with "Morcilla de Burgos".

Unidentified heterofermentative lactic acid bacterium (LAB) isolates detected earlier in vacuum or modified atmosphere (MA) packaged "Morcilla de Burgos", a Spanish cooked meat product, were identified in the present study. In the previous study, these strains had been studied by numerical analysis of HindIII RFLP- and phenotyping. However, neither of these methods had resulted in species identification. Even these unknown strains clustered together in the numerical analysis of the RFLP patterns, none of the typically meat-associated LAB type strains had clustered together with them. The phenotyping was not more useful; according to the criteria used these strains with similar HindIII ribopatterns should have been divided into four different species in three different genera. To establish the taxonomic position of these isolates, 16S rRNA gene sequence analysis, numerical analysis of EcoRI and HindIII ribopatterns, and DNA-DNA hybridization experiments were done. The 16S rRNA genes sequences of three isolates possessed the highest similarities with the corresponding sequences of Weissella species and in the phylogenetic analysis Weissella viridescens was their closest phylogenetic neighbor. However, in the numerical analysis of either HindIII or EcoRI ribopatterns the W. viridescens type strain did not cluster with these isolates. Nevertheless, the high (from 75% to 83%) DNA-DNA reassociation values between the strains studied and the W. viridescens type strain confirmed that these strains belong to the latter species. The somewhat divergent results of the pheno- and HindIII ribotyping indicate that W. viridescens is far more heterogeneous species than previously reported.

The effect of sugar concentration and starter culture on instrumental and sensory textural properties of chorizo-Spanish dry-cured sausage.

In this study, instrumental and sensory textural properties of chorizo with different levels of glucose (0.1%, 0.5% and 1.0%) and with different starter cultures (Lactobacillus sakei K29, Pediococcus sp. P22 and Pediococcus sp. P208) were studied as well as the relationship between them. The ripening process was followed by physico-chemical and microbiological analysis. Starter culture and concentration of glucose had a highly significant effect on pH, moreover an interactive effect of both factors was found; and also of day of ripening and both starter culture and concentration of glucose. In general terms, changes of pH over time are influenced by the presence of sugar and starter culture even if all chorizos showed at first a rapid decrease, a stay or slow decrease, and a final rise. Texture profile analysis (TPA) proved that hardness and chewiness differ significantly among chorizos with or without starter cultures, except in the batch with 0.1% sugar. Furthermore, the highest values in both textural parameters were found in batches with 0.5% and 1% sugar. The texture differences between chorizos just described were also noticeable in the sensorial evaluation. Likewise, instrumental textural attributes showed significant correlations with sensorial analysis.

Characterization and identification of lactic acid bacteria in "morcilla de Burgos".

A total of 176 lactic acid bacteria (LAB) isolated from a typical Spanish blood sausage called "morcilla de Burgos" were identified by means of phenotypic characteristics and 16S rDNA RFLP (ribotyping). LAB were isolated from "morcilla" of different producers and in different storage periods, which includes unpackaged, vacuum and modified atmosphere packaged "morcilla" and vacuum packed and pasteurised "morcilla". The knowledge of specific spoilage bacteria of "morcilla de Burgos" will be useful to design new preservation methods to extend the shelf-life of this product. Identification made according to phenotypic and biochemical characteristics shows the majority of the isolates were heterofermentative LAB (93.2%) and eight different bacterial groups could be distinguished (A-G). Weisella viridescens was the main species detected (42%). In addition, Leuconostoc spp. (23.9%), Weissella confusa (11.4%) and Lactobacillus fructosus (5.7%) species were found. Few strains were phenotypically misidentified as Lactobacillus sanfrancisco, Pediococcus spp., Lactobacillus sakei/curvatus and Carnobacterium spp. and 11 strains remained unknown. Most of the leuconostocs were identified as Leuconostoc mesenteroides and Leuconostoc carnosum species. Ribotyping shows a quite good correlation with phenotypic methods, although it has been possible to identify 15 different clusters. W. viridescens and leuconostocs were also the predominant LAB. Strains identified as W. confusa by phenotypic characteristics were resolved in W. confusa and Weissella cibaria by ribotyping. Neither Carnobacterium piscicola nor Lb. sanfrancisco were identified by means of genotypic method. All Lb. fructosus strains and some more included in different phenotypic groups (17 strains in total) could not be associated with any reference strain (cluster VII).

Microbiological and sensory changes in "Morcilla de Burgos" preserved in air, vacuum and modified atmosphere packaging.

"Morcilla de Burgos" is the most popular blood sausage in Spain. Traditionally, this product is distributed and sold without packaging in the local market. To extend its shelf-life and expand the market, different packaging methods have been employed and compared: "morcilla" stored in air (without packaging), in vacuum and in modified atmosphere packaging (MAP) using three different CO(2) concentrations 30%, 50% and 80% and balanced with N(2). Total viable count (TVC), psychrotrophs, lactic acid bacteria (LAB), pseudomonads, enterobacteria, moulds and yeasts, enterococci, Staphylococcus aureus, and sulfite reducing clostridia were analysed during storage at 4°C. Sulfite-reducing clostridia, pathogenic staphylococci, and enterococci were not detected in any sample. In air-stored "morcilla" a significant increase in all microbial groups was observed during storage. Pseudomonads were the predominant microorganisms reaching a population higher than 8 log cfu/g after 27 days of storage. On the other hand, a decrease in pH was noticed in MAP and in vacuum packaged "morcilla" (pH 4.73) during storage. At the same time, LAB becomes the predominant species in all these packaged samples. The rest of the microbiota did not grow during storage. In "morcilla" packed with 50% and 80% of CO(2), counts of pseudomonads and enterobacteria were lower than found in the vacuum packs. Sensory analysis showed that shelf-life of "morcilla" stored in air did not exceed 17 days, while samples packed under vacuum and with 30% CO(2) were acceptable until 22 days of storage. "Morcillas" packaged with 50% and 80% CO(2) were sensorially acceptable for 32 days.

Physicochemical and sensory characterisation of Morcilla de Burgos, a traditional Spanish blood sausage.

Morcilla de Burgos is a popular cooked blood sausage produced in the region around Burgos in the north of Spain. Physicochemical and sensory properties of this traditional product were investigated in order to support the claim for a Protected Geographical Indication. Products from 14 manufacturers were analysed for pH, water activity (a(w)), moisture, ether-extractable fat, starch, protein, total sugar, ash, iron and sodium contents as well as sensory parameters related to visual, olfactory, texture and flavour attributes. Principal component analysis confirmed the existence of three varieties of Morcilla de Burgos. Morcillas from group I were characterised by a notable blood smell and blood and pepper flavour, a high pH, and a(w) and a high protein content. Morcillas from group II were characterised by strong cumin smell and flavour and a high softness. Morcillas from group III had a high onion odour, high presence of onion and high contents of fat, total sugar and fibre.

Application of organic acid salts and high-pressure treatments to improve the preservation of blood sausage.

Blood sausages are traditional products in many parts of the world. In most cases, a very short shelf-life limits their consumption to the areas in which they are produced. In this work, different mild preservation methods were applied to Morcilla de Burgos, a Spanish blood sausage, consisting of a range of organic acid salts (OAS) and high-pressure processing (HPP), with the aim of increasing its shelf-life. In the first experiment, three batches of morcillas were produced using three different commercial OAS-PL (3% potassium lactate), PL+SL (3% potassium and sodium lactate) and PL+SD (2.5% potassium lactate and sodium diacetate)-together with a control batch and were stored under chill conditions (4 degrees C) for 35 days. In a further experiment, vacuum-packaged morcillas were treated at three different pressure levels-300, 500 and 600MPa-for 10min, and stored under chill conditions for 28 days. In both batches, a sensory difference test was performed on day 1 after treatment and the morcilla samples were subjected to microbiological and sensory analysis after each week in storage. The results suggest that, in both cases, an addition of PL+SL and the application of 600MPa for 10min increases the shelf-life of the morcillas by 15 days. Once again, it is evident that the initial opportunities for contamination play a very important role in improving the shelf-life of food products.