Bio-preservative effect of blends of essential oils: natural anti-oxidant and anti-microbial agents for the shelf life enhancement of emulsion based chicken sausages

Effect of Opuntia ficus-indica Extract in Pro-Healthy Chicken Patties: Physicochemical Properties and Oxidative Stability

Opuntia ficus-indica is a subtropical fruit rich in dietary fibers, carotenoids, vitamins, minerals, and polyphenols. To substitute synthetic additives, its extracts could become an interesting proposal to preserve quality while adding desirable characteristics to meat products. This study aimed to develop healthier chicken patties (with a structured animal fat replacer) added with prickly pear extract (PPE). The extract was analyzed for total phenolic content and antioxidant activity (FRAP, ABTS, DPPH, and ORAC). Four chicken patty formulations were manufactured with total replacement of animal fat by sesame oil emulsion: control, erythorbate 500 ppm, PPE 500, and PPE 750 ppm. Proximate composition and fatty acid profile were analyzed on day 1, and pH, color, and lipid oxidation on days 1, 4, 8, 12, and 16. PPE treatments showed lower TBARSs (p < 0.05) and greater pigment stability at the end of storage, corroborating its potential to delay oxidation reactions. No significant effects on chemical composition, pH, or fatty acid profile were observed (p > 0.05). Unsaturated represented 76.2% of total fatty acids. Therefore, PPE is an effective antioxidant by improving oxidative stability without promoting changes in other properties, besides adding cleaner label approaches and the use of natural ingredients to develop meat products reformulated with unsaturated oils.

Lyophilized Emulsions of Thymol and Eugenol Essential Oils Encapsulated in Cellulose

Efforts to tap into the broad antimicrobial, insecticidal, and antioxidant activities of essential oils (EOs) are limited due to their strong odor and susceptibility to light and oxidation. Encapsulation of EOs and subsequent drying overcome these limitations and extend their applications. This study characterized freeze-dried (lyophilized) emulsions of eugenol (EU) and thymol (TY) EOs, encapsulated by chemically unmodified cellulose, a sustainable and low-cost resource. High-resolution scanning electron microscopy showed successful lyophilization. While the observed "flake-like" structure of the powders differed significantly from that of the emulsified microcapsules, useful properties were retained. Fourier transform infrared spectroscopy confirmed the presence of EOs in their corresponding powders and thermo-gravimetric analysis demonstrated high encapsulation efficiency (87-88%), improved thermal stability and resistance to evaporation, and slow EO release rates in comparison to their free forms. The lightweight and low-cost cellulose encapsulation, together with the results showing retained properties of the dried powder, enable the use of EOs in applications requiring high temperatures, such as EO incorporation into polymer films, that can be used to protect agricultural crops from microbial infections.

Development of biomaterials based on chitosan-gelatin nanofibers encapsulated with Ziziphora clinopodioides essential oil and Heracleum persicum extract for extending the shelf-life of vacuum-cooked beef sausages

The aims of the current study were to encapsulate Ziziphora clinopodioides essential oil (ZEO, 0%, 0.15%, and 0.25%) and Heracleum persicum extract (HPE, 0%, 0.25%, and 0.5%) into the chitosan-gelatin (CH-GE) nanofibers through the electrospinning process to improve the shelf-life of vacuum-cooked beef sausages through 70 days of refrigerated storage. Scanning electron microscopy indicated that all nanofibers appeared thin, well-defined, smooth, and possessed uniform thread-like fibers without any beads or nodule formations. The Fourier transform infrared spectroscopy study confirmed the molecular interaction between encapsulated compounds and CH-GE nanofibers. The X-ray diffraction analysis of nanofibers showed an increase in crystallinity after incorporating ZEO and HPE into the polymer. Treated sausages with CH-GE-ZEO 0.25%-HPE 0.25% and CH-GE-ZEO 0.25%-HPE 0.5% showed significantly lower microbial population and lipid oxidation than the control group during the experiment period (P < 0.05). Sausages formulated with designated CH-GE nanofibers had better microbial, chemical, and sensory properties compared to sausages treated with pure ZEO/HPE during refrigerated storage. The findings also showed that treated sausages with CH-GE-ZEO 0.25%-HPE 0.5% had the highest color, odor, texture, and overall acceptability after 70 days of refrigerated storage conditions. Therefore, this treatment could be applicable for the prolonged storage conditions during cooked beef sausage production.

Nisin and Organic Acid Salts Improved the Microbial Quality, Extended the Shelf Life, and Maintained the Sensory Attributes of Semidry Beef Luncheon Marketed at Adverse (35-40 °C) Ambient Summer Temperatures

Semidry beef luncheon may undergo deteriorative changes during storage at ambient temperatures in tropical and subtropical regions including Egypt. This study was conducted in a meat plant in Egypt with the aim of overcoming the economic losses from the returns of spoiled unsold beef luncheon displayed in grocery stores at adverse summer temperatures of 37 °C or more. Ten approaches were applied using different preservatives, comprising sodium nitrite, nisin, potassium sorbate, and organic acid salts (a combination of sodium lactate, sodium acetate, and sodium diacetate). In addition, the product was cooked at different temperatures and was stored for 21 days at 37 °C, during which time the shelf life, microbial quality, pH, and sensory attributes were investigated. By Day 21 of storage, the luncheon contained 50 mg/kg sodium nitrite, 25 mg/kg nisin, and 1000 mg/kg organic acid salts and, when cooked at a final core temperature of 92 °C, exhibited reductions in aerobic plate count, anaerobic plate count, lactic acid bacterial count, and mold and yeast counts by 4.32, 3.54, 3.47, and 1.89 log10 CFU/g, respectively, when compared with the control. The sensory attributes and pH were also maintained in the final products of such treatment, with no product return and the avoidance of economic loss. This study presents a novel approach for solving the major problem of the deteriorative changes that occur in semidry luncheon sausage and similar meat products which require rejection with a huge economic loss, especially in tropical and semitropical areas of the world that have similar problems of high climatic temperatures and a low availability of energy or technological resources.

The Effect of Superficial Oregano Essential Oil Application on the Quality of Modified Atmosphere-Packed Pork Loin

During meat storage, changes in the meat colour occur, making it less intensive and red. The present study was aimed at investigating the effect of oregano EO applied directly on the surface of fresh pork on its quality, with a special emphasis on the colour. In the study, an oregano essential oil in concentrations of 0.5% and 1.0% (v/v) was used on the surface of pork loins (1.5% v/w) packed in a modified atmosphere during 15-d storage at 4 °C. The application of oregano EO in the concentration of 1.0% increased lightness and hue and decreased redness compared to the control, whereas the concentration of 0.5% did not affect the pork colour. EO did not affect pH, free water content, purge and cooking losses, cooked meat juiciness and tenderness; however, it gave the meat a distinctive herbal aroma and taste. The antimicrobial effect of 1% EO was noted only on the 15th day. Therefore, the application of oregano essential oil is not recommended to protect the colour of raw pork nor to prolong its shelf-life; however, it might be used to obtain a new product with a specific herbal aroma and taste, with modifications in water-holding capacity of the meat.

Recent development in the preservation effect of lactic acid bacteria and essential oils on chicken and seafood products

Chicken and seafood are highly perishable owing to the higher moisture and unsaturated fatty acids content which make them more prone to oxidation and microbial growth. In order to preserve the nutritional quality and extend the shelf-life of such products, consumers now prefer chemical-free alternatives, such as lactic acid bacteria (LAB) and essential oils (EOs), which exert a bio-preservative effect as antimicrobial and antioxidant compounds. This review will provide in-depth information about the properties and main mechanisms of oxidation and microbial spoilage in chicken and seafood. Furthermore, the basic chemistry and mode of action of LAB and EOs will be discussed to shed light on their successful application in chicken and seafood products. Metabolites of LAB and EOs, either alone or in combination, inhibit or retard lipid oxidation and microbial growth by virtue of their principal constituents and bioactive compounds including phenolic compounds and organic acids (lactic acid, propionic acid, and acetic acid) and others. Therefore, the application of LAB and EOs is widely recognized to extend the shelf-life of chicken and seafood products naturally without altering their functional and physicochemical properties. However, the incorporation of any of these agents requires the optimization steps necessary to avoid undesirable sensory changes. In addition, toxicity risks associated with EOs also demand the regularization of an optimum dose for their inclusion in the products.

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.

The Preservative Action of Protein Hydrolysates from Legume Seed Waste on Fresh Meat Steak at 4 °C: Limiting Unwanted Microbial and Chemical Fluctuations

Valorizing agricultural wastes to preserve food or to produce functional food is a general trend regarding the global food shortage. Therefore, natural preservatives were developed from the seed waste of the cluster bean and the common bean to extend the shelf life of fresh buffalo meat steak and boost its quality via immersion in high-solubility peptides, cluster bean protein hydrolysate (CBH), and kidney bean protein hydrolysate (RCH). The CBH and the RCH were successfully obtained after 60 min of pepsin hydrolysis with a hydrolysis degree of 27−30%. The SDS-PAGE electropherogram showed that at 60 min of pepsin hydrolysis, the CBH bands disappeared, and RCH (11−48 kD bands) nearly disappeared, assuring the high solubility of the obtained hydrolysates. The CBH and the RCH have considerable antioxidant activity compared to ascorbic acid, antimicrobial activity against tested microorganisms compared to antibiotics, and significant functional properties. The CBH and the RCH (500 µg/mL) successfully scavenged 93 or 89% of DPPH radicals. During the 30-day cold storage (4 °C), the quality of treated and untreated fresh meat steaks was monitored. Protein hydrolysates (500 g/g) inhibited lipid oxidation by 130−153% compared to the control and nisin and eliminated 31−55% of the bacterial load. The CBH and the RCH (500 µg/g) significantly enhanced meat redness (a* values). The protein maintained 80−90% of the steak’s flavor and color (p < 0.05). In addition, it increased the juiciness of the steak. CBH and RCH are ways to valorize wastes that can be safely incorporated into novel foods.

Nanoemulsion-Based Technologies for Delivering Natural Plant-Based Antimicrobials in Foods

There is increasing interest in the use of natural preservatives (rather than synthetic ones) for maintaining the quality and safety of foods due to their perceived environmental and health benefits. In particular, plant-based antimicrobials are being employed to protect against microbial spoilage, thereby improving food safety, quality, and shelf-life. However, many natural antimicrobials cannot be utilized in their free form due to their chemical instability, poor dispersibility in food matrices, or unacceptable flavor profiles. For these reasons, encapsulation technologies, such as nanoemulsions, are being developed to overcome these hurdles. Indeed, encapsulation of plant-based preservatives can improve their handling and ease of use, as well as enhance their potency. This review highlights the various kinds of plant-based preservatives that are available for use in food applications. It then describes the methods available for forming nanoemulsions and shows how they can be used to encapsulate and deliver plant-based preservatives. Finally, potential applications of nano-emulsified plant-based preservatives for improving food quality and safety are demonstrated in the meat, fish, dairy, and fresh produce areas.

Application of essential oils as antimicrobial agents against spoilage and pathogenic microorganisms in meat products

Meat and meat products are perishable products that require the use additives to prevent the spoilage by foodborne microorganisms and pathogenic bacteria. Current trends for products without synthetic preservatives have led to the search for new sources of antimicrobial compounds. Essential oils (EOs), which has been used since ancient times, meet these goals since their effectiveness as antimicrobial agents in meat and meat products have been demonstrated. Cinnamon, clove, coriander, oregano, rosemary, sage, thyme, among others, have shown a greater potential to control and inhibit the growth of microorganisms. Although EOs are natural products, their quality must be evaluated before being used, allowing to grant the Generally Recognized as Safe (GRAS) classification. The bioactive compounds (BAC) present in their composition are linked to their activity, being the concentration and the quality of these compounds very important characteristics. Therefore, a single mechanism of action cannot be attributed to them. Extraction technique plays an important role, which has led to improve conventional techniques in favour of green emerging technologies that allow to preserve better target bioactive components, operating at lower temperatures and avoiding as much as possible the use of solvents, with more sustainable processing and reduced energy use and environmental pollution. Once extracted, these compounds display greater inhibition of gram-positive than gram-negative bacteria. Membrane disruption is the main mechanism of action involved. Their intense characteristics and the possible interaction with meat components make that their application combined with other EOs, encapsulated and being part of active film, increase their bioactivity without modifying the quality of the final product.