Effect of Dietary Treatment with Olive Oil By-Product (Olive Cake) on Physicochemical, Sensory and Microbial Characteristics of Beef During Storage

Diet supplemented with olive cake as a model of circular economy: Metabolic and endocrine responses of beef cattle

Introduction

Integrating by-products into livestock diet represents a great opportunity for implementing the concept of circular economy while reducing feed costs. Olive cake (OC) is considered an agro-industrial waste, but the high content of valuable metabolites makes it a promising feed integration. Therefore, this study investigated the effect of OC integration in beef cattle diet on different blood parameters.

Methods

Forty-eight young growing fattening Limousines-−24 bulls (body weight 350 ± 15 kg) and 24 heifers (280 ± 10 kg)—, aged 240 ± 20 days, were randomly allocated to 1 of 3 dietary treatments: concentrate at 0% (Control group: CTR), 10% (Low-olive cake group: L-OC), or 15% (High-olive cake group: H-OC) of OC inclusion. Blood samples and body weights were collected before administrating the supplemented diet (0 d), at the end of the stocker growing phase (56 d), and at the end of the fattening (147 d). After being slaughtered, animal carcasses were weighted. A linear regression model was fitted for each blood parameter with the 0 d as covariate and diet, time, sex, diet × time, and diet × sex as fixed effects.

Results

In males, body weight was highest in CTR, but carcass weight was similar in all the groups. All the blood parameters were within physiological ranges, independently from the animal diet. CTR group showed the highest alanine aminotransferase (ALT, P = 0.0027) and creatine kinase (P = 0.0119), whereas total bilirubin (P = 0.0023) was higher in H-OC than in CTR. Moreover, ALT was highest in CTR at 56 d, becoming similar in all the groups at 147 d (P = 0.0280). Instead, the increase observed in total cholesterol from 56 to 147 d was lower in H-OC compared with CTR and L-OC (P = 0.0451). A significant effect of diet × sex interaction was observed on triglycerides, urea, liver enzymes, and insulin. These data support the OC inclusion of up to 15% of the concentrate with no detrimental effect on beef cattle metabolic status.

Discussion

In conclusion, OC can be considered as a component in beef diet giving an opportunity to improve agriculture sustainability.

Dietary Polyphenol Supplementation in Food Producing Animals: Effects on the Quality of Derived Products

Simple Summary

Polyphenols are secondary plant metabolites mainly known for their antioxidant properties. Their use as feed additives in the nutrition of farm animals is becoming increasingly popular as they are particularly exposed to oxidative stress which is reflected in a lipoperoxidation of the final product. For this reason, it is essential to preserve the quality and the safety of meat and milk products by attenuating oxidative deterioration. Moreover, polyphenols present the advantage of being more acceptable to the consumers than synthetic counterparts, as they are considered to be “non-toxic”. The present review presents an overview of several studies focused on the dietary supplementation of polyphenols to monogastric and ruminants, as well as their direct addition to meat and dairy products, with particular emphasis on their antioxidant effects on the final product.

Abstract

The growing interest in producing healthier animal products with a higher ratio of polyunsaturated to saturated fatty acids, is associated with an increase in lipoperoxidation. For this reason, it is essential to attenuate oxidative deterioration in the derived products. Natural antioxidants such as polyphenols represent a good candidate in this respect. The first part of the review highlights the occurrence, bioavailability, and the role of polyphenols in food-producing animals that, especially in intensive systems, are exposed to stressful situations in which oxidation plays a crucial role. The second part offers an overview of the effects of polyphenols either supplemented to the diet of monogastric and ruminants or added directly to meat and dairy products on the physicochemical and sensorial properties of the product. From this review emerges that polyphenols play an important, though not always clear, role in the quality of meat and meat products, milk and dairy products. It cannot be ruled out that different compounds or amounts of polyphenols may lead to different results. However, the inclusion of agro-industrial by-products rich in polyphenols, in animal feed, represents an innovative and alternative source of antioxidants as well as being useful in reducing environmental and economic impact.

Dietary Supplementation with Olive Mill Wastewater in Dairy Sheep: Evaluation of Cheese Characteristics and Presence of Bioactive Molecules

Simple Summary

Using polyphenols from olive oil waste as feed supplements in animal diets can be a strategy to reduce adverse environmental effects of this by-product and to enhance the quality of products of animal origin. The aim of the study was to assess the effects of adding a polyphenolic concentrate from olive oil wastewater to a typical sheep diet on the nutraceutical and quality characteristics of cheese. The experiment was carried out on thirty-six Sarda ewes, divided into two homogenous groups fed a standard diet composed of hay and concentrate. In one of the two diets, the concentrate was supplemented (25 g/kg) with polyphenols obtained from olive mill wastewater using a special filtration system. Data showed that the polyphenol supplementation in the ewe’s diet resulted in the presence of tyrosol and hydroxytyrosol sulphate metabolites in milk and cheese. Furthermore, these compounds were able to provide a direct antioxidant effect on cheese with no modification in its chemical composition.

Abstract

The aim of the study was to define the chemical characteristics, antioxidant capacity, oxidative status, sensory properties, and the presence of polyphenols in ovine cheese obtained after dietary administration of spray-dried olive mill wastewater (SDP). SDP is a waste from olive oil production rich in bioactive molecules obtained by further processing the olive mill wastewater through a spray-drying system. Thirty-six sheep were randomly assigned to two experimental groups that received a standard diet based on hay and concentrate. The concentrate fed to the SDP group was supplemented with SDP at a rate 25 g/kg (as fed). The trial lasted 9 weeks. Milk from the two treatment groups was separately collected and used for manufacturing cheese. Cheese quality parameters and proximate composition were not affected by the dietary treatment, whereas the antioxidant status and oxidative stability of cheese were positively affected. Polyphenol analyses in cheese were performed through liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The concentration of hydroxytyrosol and tyrosol, and their sulphate metabolites, were higher in cheese from supplemented sheep. These findings suggest that polyphenol metabolites can play a major role in the beneficial effects observed in food produced from sheep fed SDP.

The impact of dietary supplementation with guava (Psidium guajava L.) agroindustrial waste on growth performance and meat quality of lambs

The aim of this study was to evaluate the growth performance and meat quality of lambs (40 animals) fed with increasing levels (0; 7.5; 15.0; 22.5 and 30.0%) of guava agroindustrial waste (GAW). The pH, cooking loss, colour and chemical composition were measured in the Longissimus lumborum (LL) muscle. A sensory analysis was performed with a panel of eight trained testers using a quantitative descriptive method in order to define sensory descriptors and their intensities. The lambs obtained a mean weight gain of 316 g/day consuming 1.32 kg/day of dry matter. The inclusion of GAW in the diet of lambs did not affect pH, L*, a* and b*. However, significant difference (P < .05) among the treatments were obtained for the chemical composition of LL: moisture decreased, while ash increased and intramuscular fat increased until 15% and then decreased at 22.5% with the inclusion of GAW. However, the sensorial characteristics of lamb meat (lamb odour and flavour, tenderness and juiciness) were not affect by the inclusion of GAW. Therefore, GAW can be included up to 30% in lamb feed without compromising the performance, physic-chemical and sensory characteristics of meat.

Effects of adding solid and molten chocolate on the physicochemical, antioxidant, microbiological, and sensory properties of ewe's milk cheese

A novel dairy product, namely "chocolate cheese", was produced with two typical Sicilian food products: Pecorino cheese, processed from ewe's milk, and Modica chocolate. The cheese, manufactured with 0%, 5%, 10%, and 15% (w/w) solid or molten chocolate, was evaluated after 0, 2, 4, and 6 weeks of vacuum storage for its nutritional and health properties. The addition of chocolate reduced the pH, protein, fat, and ash; the addition of 5% or 10% molten chocolate reduced hardness (N/mm² ). The addition of either solid or molten chocolate resulted in a slight increase (P < 0.1038) in the total polyphenol content, a higher oleic acid content, and less oxidative stability. The microbiological profile showed that the total mesophilic count and the number of mesophilic coccus lactic acid bacteria (LAB) were approximately equal (about 10⁸ CFU/g) in all cheese. The survival of the microorganisms was affected by both the chocolate added and the storage time. Chocolate cheese stored for 6 weeks had less Enterobacteriaceae than control cheese, whereas yeasts were detected at higher cell densities in the former cheese. Filamentous fungi were undetectable in some cheese. Differences were also observed in the number of mesophilic rod LAB, which increased progressively over time in all cheese, and in Enterobacteriaceae, yeasts, and filamentous fungi, which decreased during storage. Descriptive and hedonic sensory tests and principal component analysis showed that fresh cheese and cheese stored for 2 weeks, including 5% molten chocolate, were the most preferred by evaluators. Based on these results, chocolate cheese has the potential to be appreciated in the market for its nutritional, health, and sensory properties. PRACTICAL APPLICATION: Chocolate cheese, made by combining two typical Sicilian foods, Pecorino cheese and Modica chocolate, is proposed as a novel dairy product. The highest sensory acceptance was obtained with the addition of 5% molten chocolate and storage for 2 weeks. Given its improved antioxidant properties, healthier fat, and sensory properties, chocolate cheese has the potential to be appreciated in the market, especially by young consumers.

Effects of Dried Olive Pulp Dietary Supplementation on Quality Characteristics and Antioxidant Capacity of Pig Meat

Olive pulp belongs to agro-industrial by-products, and its addition into livestock diets generally result in neutral or positive effects on performance. However, the data concerning the effects of olive by-products on pork meat characteristics are scarce. The aim of this preliminary study was therefore to examine the effects of dried olive pulp (DOP) dietary supplementation on quality parameters and oxidative stability of pig meat. Twenty finishing pigs were allocated to two groups: C that was provided with a control diet, and DOP that was fed with an isonitrogenous and isoenergetic diet supplemented with dried olive pulp at the level of 50 g/kg or 5%. As indicated, cold carcass weight, pH, lightness, redness, cooking loss, and tenderness were not influenced by DOP inclusion. Only meat yellowness (a*) was significantly decreased in DOP meat samples. Moreover, meat oxidation values tended to decrease in the DOP group after one day, but no further differences were observed after four, six, and eight days of refrigerated storage. It can be concluded that DOP dietary supplementation could be recommended as a feasible approach, especially in the Mediterranean region to reduce diet formulation costs, while no significant side effects on pork meat quality are observed.

Olive mill wastewater phenolic concentrate as natural antioxidant against lipid-protein oxidative deterioration in chicken meat during storage

Considering that many plant-derived substances show antioxidant and antimicrobial properties, natural antioxidant administered through feed in livestock animals could increase the shelf life of meat and meat products. The aim of this work was to study the effect of olive oil by-products on chicken meat lipid and protein oxidation and oxidative stability during storage. Two hundred and ninety-seven 22-day-old fast growing (Ross 308) female chicks were randomly assigned to three experimental grower-finisher diets: i) a basal control diet (CTR), ii) CTR diet supplemented with a low dosage (4.8%) of olive mill wastewater extract (L-OW) and iii) CTR diet supplemented with a high dosage (9.9%) of olive mill wastewater extract (H-OW). Breast meat of animals belonging to each experimental group was sliced, overwrapped with oxygen-permeable packaging and analysed at three different storage times (zero, three and seven days). At the three sampling times considered, for all samples, colour coordinates (a*), saturation index, Hue angle, peroxide value, thiobarbituric reactive substance, carbonyl assay and the oxygen radical absorbance capacity determinations were performed. No differences in colour were detected among the groups in all the sampling times considered. In conclusion, the supplementation of chicken diet with olive mill wastewater extract (OW) affected oxidation of meat, retarding lipid and protein oxidation and improving antioxidant activity during storage.

Microbiological, chemical-physical and sensory characteristics of Fabriano salami from pigs fed Oregano vulgaris extract

This study aimed at evaluating the effect of Oregano vulgaris extract supplementation of heavy pig diet on the microbiological, chemical-physical and sensory characteristics of Fabriano salami. Fabriano salamis were produced processing meat derived from pigs belonging to two dietary groups of 16 pigs each: CTRL group fed a commercial pelleted feed, and OR group fed the CTRL diet integrated with 0.2% of oregano extract. Ten salamis per group were collected at 0, 7, 20 and 45 days of ripening and analysed for total viable count, enumeration of Enterobacteriaceae, Enterococcus spp, coagulase negative and positive staphylococci, Lactobacillus spp., Lactococcus spp., presence of Salmonella spp. and Listeria monocytogens, pH, water activity (a^w) and colour (CIE L*a*b* colour system). At the end of the ripening (day 45) chemical composition (AOAC, 1990), total antioxidant capacity (ORAC_FL), thiobarbituric reactive substances (TBARS), total phenolic content (TPC) (Folin-Ciocalteu method) and consumer tests were performed. The integration of oregano extract in pig diets did not interfere with the microbial evolution, chemical composition, pH and a_w. After 20 days of ripening the OR salami were redder then CTRL samples, which were also yellower at the end of ripening. Furthermore, the diet has significantly improved the oxidative status, the polyphenolic content and antioxidant power in OR salami. The consumers gave a higher score to OR salami in informed condition.

Effect of mixed feeds containing different levels of olive cake on fattening performance, carcass, meat quality and fatty acids of lambs

In this study, the effects of diet including different levels of olive cake were investigated on the fattening performance, blood parameters, certain slaughtering traits, and carcass quality of lambs. Thirty-six male lambs were used in the experiment. The lambs were randomly assigned to three groups with 12 lambs each. Groups included control, 12.5 and 25% olive cake (OC). The mixed feeds were offered ad libitum. All lambs were also allowed to consume alfalfa hay (83.8 g DM/animal/day). The experiment lasted for a period of 56 days. The effect of different levels of olive cake was not found different in fattening performance values of lambs in 0-56 days (P > 0.05). Carcass weight, pH, and yield were not different (P > 0.05). While the values of color parameters, cooking loss, tenderness, and ether extract level of longissimus dorsi muscle (MLD) was not found different (P > 0.05), it was determined that the levels of olive cake increased the water-holding capacity of meat (P < 0.05). Furthermore, although the levels of olive cake were shown to decrease total n-3 and total saturated fatty acids (Σ SFA), they also increased total n-6, n-6/n-3 ratio, total monounsaturated fatty acids (Σ MUFA), and total polyunsaturated fatty acids (Σ PUFA) were not different (P > 0.05).

Dietary integration with oregano (Origanum vulgare L.) essential oil improves growth rate and oxidative status in outdoor-reared, but not indoor-reared, pigs

The effects of a diet supplemented with oregano essential oil on performance, oxidative status, pork quality traits and sensorial properties were evaluated. In two studies, 72 pigs in indoor or outdoor conditions were assigned to either a control diet or an identical diet supplemented with 0.2% oregano essential oil. Pigs reared outdoor showed lower live weight, average daily gain and average gain:feed ratio compared to indoor pigs. The oregano supplementation improved the growth performance of the outdoor- but not the indoor-reared animals. The serum oxidative status was influenced by the diet. A higher oxidative stability was observed in the oregano-supplemented groups. As for the rearing conditions, the data suggest that after an initial adapting period, the free-range farming systems could be better tolerated by pigs. Meat derived from pigs reared outdoor showed higher pH and a* values. Lightness was influenced by both the diet and the rearing conditions. The control group reared indoor showed shear force values higher than both supplemented groups, while no differences were detected with the control group reared outdoor. In the consumer test performed under blind conditions, the oregano groups achieved higher consistency scores compared with the control. Under informed conditions, the meat derived from the oregano-supplemented pigs reared outdoor received the highest scores for consistency and overall liking regardless of the rearing system. The same result for the overall liking score was obtained in the expectation test. The data obtained showed that dietary oregano essential oil can be effective in reducing performance losses due to the outdoor-rearing system, increasing the oxidative status of the animal and oxidative stability of the meat, without modifying the meat quality traits and improving consumer perceptions of the meat quality.

Effect of a Phenolic Extract from Olive Vegetation Water on Fresh Salmon Steak Quality during Storage

This study aimed to evaluate the antioxidant and antimicrobial effects of a phenolic extract from olive vegetation water on fresh salmon steaks stored at 4°C under modified atmosphere. Twenty-four salmon steaks were respectively immersed in solutions of the diluted phenolic extract at 1.5 g/L (A), 3 g/L (B), and water only as a control (CTR), packaged within a protective atmosphere (70% carbon dioxide, 25% nitrogen and 5% oxygen) and then stored at 4°C. After 2 h, and 3 and 6 days of storage, the fish samples were analysed for the total viable count, Enterobacteriaceae count, pH, colour (CIE L*a*b* colour system), phenolic composition, atocopherol content, antioxidant activity by 2,2- diphenyl- 1-picrylhydrazyl (DPPH˙) assay, and thiobarbituric reactive substances (TBARS). A 3 g/L phenolic extract contributed positively to the hygienic quality of the salmon by reducing the microbial growth during storage. The treated samples were slightly yellower than the CTR but only at the beginning of storage. The flesh contained 6.2% of the total polyphenols present in the initial solutions, with various percentages of the single fractions. After 6 days storage, the α- tocopherol content in the CTR and A samples was statistically lower than the B group that also showed the lowest DPPH˙ and TBARS values. In conclusion, the phenolic extract increased the microbiological quality and antioxidant concentration and decreased the lipid oxidation of salmon steaks during storage at 4°C under modified atmosphere.

Antimicrobial Activity of Olive Mill Wastewater Extract Against Pseudomonas Fluorescens Isolated from Mozzarella Cheese

Olive mill wastewater polyphenol extract was tested for antimicrobial activity against 64 strains of Pseudomonas fluorescens responsible for mozzarella discolouration. The extract showed a minimum inhibitory concentration (MIC)₅₀ value of 5 mg/mL and a MIC₉₀ value of 7 mg/mL. The MBC₅₀ and MBC₉₀ values corresponded to 6 and 8 mg/mL, respectively. The MIC concentration (7 mg/mL) was demonstrated to have a bacteriostatic effect while maintaining the bacterial concentration on the levels of the inoculum for 48 hours. The 3/2 MIC concentration was responsible for four logs CFU/mL depletion in colony count after 24 h. As the extract concentration decreased from MIC value, no inhibitory effects were recorded.