Combined Effect of an Active AgIon® Absorbent Pad and a Chitosan Coating on the Preservation of Fresh Beef.

In the present study, the combined effect of an AgIon® antimicrobial absorbent (Ζ) pad and a chitosan coating (C) on the preservation of fresh beef stored aerobically at 5 °C was investigated. Microbiological, physicochemical, and sensory attributes were monitored for up to 10 days of storage. The microbiological data indicated that the C and chitosan coating plus absorbent pad (CZ) treatments were the most efficient in reducing total viable counts (TVC) by 4.09 and 3.53 log cfu/g compared to the control W and Z treatments on day 4 of storage (p < 0.05). An analogous reduction in the counts of the other microbial groups monitored was recorded. pH values were ca. 5.7 for treatments W and Z and 5.45 for treatments C and CZ on day 4 of storage (p < 0.05). The total volatile basic nitrogen (TVB-N) values remained <20 mg/100 g for all treatments on day 4 and for treatments C and CZ on day 10 of storage. The total color difference values decreased (p < 0.05) during storage for treatments W and Z, but remained constant for treatments C and CZ. Based on sensory, microbiological and physico-chemical data, beef shelf life was ca ^# + 3 days for samples W and Z and at least 10 + 3 days for samples C and CZ. Between the two antimicrobial treatments, chitosan was considerably more effective than the AgIon® antimicrobial absorbent pad, which showed practically no antimicrobial activity in direct contact with beef meat.

Analytical insights for ensuring authenticity of Greek agriculture products: Unveiling chemical marker applications.

Food authentication, including the differentiation of geographical or botanical origin, the method of production i.e. organic vs. conventional farming as well as the detection of food fraud/adulteration, has been a rapidly growing field over the past two decades due to increasing public awareness regarding food quality and safety, nutrition, and health. Concerned parties include consumers, producers, and legislators. Thus, the development of rapid, accurate, sensitive, and reproducible analytical methods to guarantee the authenticity of foods is of primary interest to scientists and technologists. The aim of the present article is to summarize research work carried out on the authentication of Greek agricultural products using spectroscopic (NIR, FTIR, UV-Vis, Raman and fluorescence spectroscopy, NMR, IRMS, ICP-OES, ICP-MS) and chromatographic (GC, GC/MS, HPLC, HPLC/MS, etc.) methods of analysis in combination with chemometrics highlighting the chemical markers that enable product authentication. The review identified a large number of chemical markers including volatiles, phenolic substances, natural pigments, elements, isotopes, etc. which can be used for (i) the differentiation of botanical/geographical origin; conventional from organic farming; production procedure and vintage year, etc. and (ii) detection of adulteration of high quality plant and animal origin foods with lower value substitutes. Finally, the constant development of reliable analytical techniques in combination with law enforcement authorities will ensure authentic foods in terms of quality and safety for consumers.

Evaluation of a New Bulk Packaging Container for the Ripening of Feta Cheese.

In the present study, the quality characteristics of Feta cheese were investigated as a function of the packaging container (a stainless-steel tank (SST), a wooden barrel (WB), and a tin can (TC)) and ripening time. The results showed that the Feta cheese's pH, moisture, and lactose decreased, while fat, protein, and salt increased (p < 0.05) during ripening with SST and WB, showing similar behaviors versus that of the TC container. For the proteolysis indices, % TN,% WSN, 12% TCA, and 5% PTA showed the highest values (p < 0.05) for cheeses packaged in WB, followed by those in SST and TC, with all increasing (p < 0.05) during ripening. The most abundant odor-active volatiles were free fatty acids, alcohols, and esters following the order SST > WB > TC on day 60. On day 60, the cheeses packaged in SST and WB showed higher (p < 0.05) hardness and fracturability values, as well as aroma scores, compared to those in TC, with both parameter values increasing with the ripening time.

Characterization and Differentiation of Fresh Orange Juice Variety Based on Conventional Physicochemical Parameters, Flavonoids, and Volatile Compounds Using Chemometrics.

The present study focused on the possibility of differentiating fresh-unprocessed orange juice according to botanical origin (variety), based on the use of conventional physico-chemical parameters, flavonoids, and volatile compounds, in combination with chemometrics. For this purpose, oranges from seven different varieties were collected during the harvest years of 2013−2014 and 2014−2015 from central and southern Greece. The physico-chemical parameters that were determined included: electrical conductivity, acidity, pH, and total soluble solids. The flavonoids: hesperidin, neohespseridin, quercetin, naringin, and naringenin were determined using high-performance liquid chromatography (HPLC-DAD). Finally, volatile compounds were determined using headspace solid-phase micro-extraction in combination with gas chromatography-mass spectrometry (HS-SPME/GC-MS). Statistical treatment of data by multivariate techniques showed that orange juice variety had a significant (p < 0.05) impact on the above analytical parameters. The classification rate for the differentiation of orange juice according to orange variety using multivariate analysis of variance (MANOVA) and linear discriminant analysis (LDA) was 89.3%, based on the cross-validation method.

Combined Effect of Chitosan Coating and Laurel Essential Oil (Laurus nobilis) on the Microbiological, Chemical, and Sensory Attributes of Water Buffalo Meat.

The combined effect of chitosan coating (CHI) and laurel essential oil (LEO) on the shelf-life extension of water buffalo meat stored under aerobic packaging conditions at 4 °C was investigated. Microbiological, physicochemical, and sensory attributes were monitored over an 18-day storage period. Microbiological data indicated that the (CHI) coating along with (LEO) was the most efficient among treatments in reducing populations of bacteria by 3.2 log cfu/g on day 6 of storage (p < 0.05). pH values of meat varied between 6.04 and 6.21, while thiobarbituric acid (TBA) values were equal to or less than 2.12 mg malondialdehyde/kg throughout storage. The colour parameter L* and a* values decreased, while b* values increased during storage (p < 0.05). Taste proved to be a more sensitive sensory attribute than odour. Based on sensory and microbiological data, product shelf life was approximately 5−6 days for control samples, 7−8 days for samples treated with (LEO), 12 days for samples treated with (CHI), and 13−14 days for samples treated with (CHI + LEO).

Profile of Volatile Compounds in Dessert Yogurts Prepared from Cow and Goat Milk, Using Different Starter Cultures and Probiotics.

The purpose of this study was to determine the profile of volatile compounds (aroma) and overall flavor in dessert yogurts prepared from cow and goat milk, using three different, commercially available starter cultures, in the presence or absence of probiotic bacteria and to correlate this to organoleptic evaluation results obtained using a consumer acceptability method. The extraction of volatile compounds was carried out by solid phase micro-extraction; separation and analysis by gas chromatography-mass spectrometry. Variations among the different classes of compounds (i.e., aldehydes, alcohols, ketones, volatile acids, hydrocarbons, and terpenes) were recorded for different treatments. The results showed that the main volatiles in the cow milk dessert yogurts without Bifidobacterium BB-12 were: acetaldehyde, 2,3-butanedione, 2,3-pentanedione, 3-OH-2-butanone, 2-propanone, hexanoic acid and limonene). Respective volatiles in cow milk dessert yogurts with Bifidobacterium BB-12 were: acetaldehyde, pentanal, hexanal, the same ketones, acetic acid and limonene). The volatiles in goat milk dessert yogurts without Lactobacillus acidophilus LA-5 were: acetaldehyde, the same ketones, no carboxylic acids, limonene, camphene, α- and ß-pinene. Respective volatiles in goat milk dessert yogurts with Lactobacillus acidophilus LA-5 were: aldehydes acetaldehyde, the same ketones, butanoic acid, α-pinene and camphene varying in concentration in different samples. Based on the results of volatiles and organoleptic evaluation, it can be concluded that dessert yogurts from cow milk without probiotic bacterial strains using the mild and classic starter cultures, and dessert yogurts from goat milk with probiotic bacterial strains using the classic and acidic starter cultures are found to be more organoleptically acceptable by consumers. In most cases, a positive correlation was found between dessert yogurt organoleptically determined flavor and volatiles (aldehydes, ketones and carboxylic acids).

Characterization of Artisanal Spontaneous Sourdough Wheat Bread from Central Greece: Evaluation of Physico-Chemical, Microbiological, and Sensory Properties in Relation to Conventional Yeast Leavened Wheat Bread.

In the present study, both yeast leavened bread (YLB) and artisanal sourdough wheat bread (SDB) were prepared. The physico-chemical, microbiological, and sensory properties of breads were monitored as a function of storage time (T = 25 °C). As expected, the titratable acidity (TA) values of SDB were higher than those of YLB. The aroma profile of SDB was similar to that of YLB, including classes of compounds such as alcohols, aldehydes, ketones, esters, organic acids, terpenes, and sulfur compounds; however, the concentrations between the two were different. Aroma deterioration of bread during storage was partly related to the loss of several volatiles. Texture and sensory analysis showed that SDB was harder, less elastic, but richer in aroma and light sour taste than YLB. Mold growth was apparent when the population of yeasts/molds reached approximately 4 log cfu/g. This yeast/mold count was reached on days 4-5 for YLB and day 18 + for SDB. A 16S amplicon meta-barcoding analysis showed that the bacterial profile of SDB was dominated by a single genus, (Lactobacillus). Analysis of the eukaryotic load showed that at the genus level, Saccharomyces and Alternaria were the most abundant genera, independently of the gene sequenced (18S or ITS). Based primarily on mold growth and texture data, which proved to be the most sensitive quality parameters, the shelf life was ca. 4-5 days for YLB and 10 days for SDB.

Effect of Frying and Roasting Processes on the Oxidative Stability of Sunflower Seeds (Helianthus annuus) under Normal and Accelerated Storage Conditions.

The effect of different cooking processes such as frying and roasting on the oxidative stability of sunflower seeds was evaluated under accelerated oxidation and normal storage conditions. The fatty acid composition by GC-MS showed a higher amount of linoleic acid in fried samples due to the replacement of the seed moisture by the frying oil. On the other hand, roasted samples presented a higher oleic acid content. DSC and TGA results showed some decrease in the thermal stability of sunflower seed samples, whereas PV and AV showed the formation of primary and secondary products, with increasing oxidation time. Roasted sunflower seeds showed seven main volatile compounds characteristic of the roasting process by HS-SPME-GC-MS: 2-pentylfuran, 2,3-dimethyl-pyrazine, methyl-pyrazine, 2-octanone, 2-ethyl-6-methylpyrazine, trimethyl-pyrazine, and trans,cis-2,4-decadienal, whereas fried samples showed six volatile characteristic compounds of the frying process: butanal, 2-methyl-butanal, 3-methyl-butanal, heptanal, 1-hexanol, and trans,trans-2,4-decadienal. The generation of hydroperoxides, their degradation, and the formation of secondary oxidation products were also investigated by ATR-FTIR analysis. The proposed methodologies in this work could be suitable for monitoring the quality and shelf-life of commercial processed sunflower seeds with storage time.

Recent Developments in Seafood Packaging Technologies.

Seafood products are highly perishable, owing to their high water activity, close to neutral pH, and high content of unsaturated lipids and non-protein nitrogenous compounds. Thus, such products require immediate processing and/or packaging to retain their safety and quality. At the same time, consumers prefer fresh, minimally processed seafood products that maintain their initial quality properties. The present article aims to review the literature over the past decade on: (i) innovative, individual packaging technologies applied to extend the shelf life of fish and fishery products, (ii) the most common combinations of the above technologies applied as multiple hurdles to maximize the shelf life of seafood products, and (iii) the respective food packaging legislation. Packaging technologies covered include: Modified atmosphere packaging; vacuum packaging; vacuum skin packaging; active food packaging, including oxygen scavengers; carbon dioxide emitters; moisture regulators; antioxidant and antimicrobial packaging; intelligent packaging, including freshness indicators; time-temperature indicators and leakage indicators; retort pouch processing and edible films; coatings/biodegradable packaging, used individually or in combination for maximum preservation potential.

Shelf life evaluation of fresh chicken burgers based on the combination of chitosan dip and vacuum packaging under refrigerated storage.

The aim of the present study was to investigate the combined effect of chitosan dip (1% w/v) and vacuum packaging on the shelf life of fresh chicken burgers packaged in LDPE/PA/LDPE bags and stored at 4 ± 1 °C for up to 12 days. Furthermore, the possible correlation among microbiological, physico-chemical and sensory indices was investigated. Burger treatments included: aerobic packaging (AP, control), vacuum packaging (VP), chitosan dipping (CHI), and vacuum packaging plus chitosan dipping (VP + CHI). Microbiological [Total viable count (TVC), Pseudomonas spp., Brochothrix thermosphacta, Enterobacteriaceae, Lactic acid bacteria (LAB)], physicochemical [color, pH, total volatile basic Nitrogen (TVB-N), and Thiobarbituric acid (TBA)] and sensory (odor, taste, and texture) analyses were carried out. Results showed that the majority of microbiological, physico-chemical, and sensory analysis parameters varied significantly (p < 0.05) depending on treatment. Based primarily on sensory, followed by microbiological and physico-chemical data, the shelf life of chicken burgers was 4 days for AP samples, 8 days for VP samples, 10 days for CHI treated samples, and 12 days for the VP + CHI treated samples. Finally, a positive and significant correlation (p < 0.05) was observed among most microbiological, sensory, and physico-chemical data, introducing new data relating initial TVC to TVB-N values regarding alternative treatments of minced chicken meat for its optimum preservation.

Innovative Seafood Preservation Technologies: Recent Developments.

Fish and fishery products are among the food commodities of high commercial value, high-quality protein content, vitamins, minerals and unsaturated fatty acids, which are beneficial to health. However, seafood products are highly perishable and thus require proper processing to maintain their quality and safety. On the other hand, consumers, nowadays, demand fresh or fresh-like, minimally processed fishery products that do not alter their natural quality attributes. The present article reviews the results of studies published over the last 15 years in the literature on: (i) the main spoilage mechanisms of seafood including contamination with pathogens and (ii) innovative processing technologies applied for the preservation and shelf life extension of seafood products. These primarily include: high hydrostatic pressure, natural preservatives, ozonation, irradiation, pulse light technology and retort pouch processing.

The Application of Chemometrics to Volatile Compound Analysis for the Recognition of Specific Markers for Cultivar Differentiation of Greek Virgin Olive Oil Samples.

In the present study, volatile compound analysis of olive oil samples belonging to ten Greek cultivars was carried out. A total of 167 olive oil samples collected from two consecutive harvest years were analyzed by Head Space-Solid Phase Microextraction-Gas Chromatography/Mass Spectrometry (HS-SPME-GC/MS). Volatile compound data were combined with chemometric methods (Multivariate Analysis of Variance (MANOVA) and Linear Discriminant Analysis (LDA)) with the aim not only to differentiate olive oils but also to identify characteristic volatile compounds that would enable differentiation of botanical origin (marker compounds). The application of Stepwise LDA (SLDA) effectively reduced the large number of statistically significant volatile compounds involved in the differentiation process, and thus, led to a set of parameters, the majority of which belong to compounds that are highly dependent on variety. In addition, the use of these marker compounds resulted in an increased correct classification rate (85.6%) using the cross-validation method indicating the validity of the model developed despite the use of a large number of dependent variables (cultivars).

Use of Alginates as Food Packaging Materials.

Packaging mainly functions by protecting and preserving its contents. In the case of food packaging, the package protects the contained food product from (i) physical/mechanical damage; (ii) physico-chemical changes due to the effect of light, oxygen, moisture and odors; and (iii) biological changes due to the presence of microorganisms and pests; all the above parameters result in the reduction in product quality and safety. Due to the negative impact of synthetic packaging materials on the environment, research organizations as well as the food industry are currently exploring the possibility of using biodegradable and renewable materials deriving from natural sources. Such biopolymers include: proteins (whey proteins, wheat, corn and soy proteins, gelatin), lipid derivatives (waxes, acetylated triglycerides) and carbohydrates (starch, cellulose and its derivatives, carrageenan, pectin, chitosan, alginates) used in food packaging applications. Alginates are natural hydrophilic polysaccharide biopolymers mainly extracted from marine brown algae. In the form of films or coatings, they exhibit: good film-forming properties, low permeability to O2 and vapors, flexibility, water solubility and gloss while being tasteless and odorless. When combined with additives such as organic acids, essential oils, plant extracts, bacteriocins and nanomaterials, they contribute to the retention of moisture, reduction in shrinkage, retardation of oxidation, inhibition of color and texture degradation, reduction in microbial load, enhancement of sensory acceptability and minimization of cooking losses. Alginates were initially used as a coating for perishable fresh fruits and vegetables to control respiration rate, but can be applied to a wide range of foods, such as meat, poultry, seafood and cheese products, resulting in the extension of product shelf life. When used as part of the principle of active, intelligent and green packaging technologies, alginates can work synergistically to yield a multi-function food packaging system comprising the ultimate goal of food packaging technology.

Physicochemical, Spectroscopic, and Chromatographic Analyses in Combination with Chemometrics for the Discrimination of the Geographical Origin of Greek Graviera Cheeses.

Seventy-eight graviera cheese samples produced in five different regions of Greece were characterized and discriminated according to geographical origin. For the above purpose, pH, titratable acidity (TA), NaCl, proteins, fat on a dry weight basis, ash, fatty acid composition, volatile compounds, and minerals were determined. Both multivariate analysis of variance (MANOVA) and linear discriminant analysis (LDA) were applied to experimental data to achieve sample geographical discrimination. The results showed that the combination of fatty acid composition plus minerals provided a correct classification rate of 89.7%. The value for the combination of fatty acid compositions plus conventional quality parameters was 94.9% and for the combination of minerals plus conventional quality parameters was 97.4%. When cheeses of the above five geographical origins were combined with previously studied graviera cheeses from six other geographical origins collected during the same seasons in Greece, the respective values for the discrimination of geographical origin of all eleven origins were 89.3% for conventional quality parameters plus minerals; 94.0% for conventional quality parameters plus fatty acids; 94.1% for minerals plus fatty acids; and 95.2% for conventional quality parameters plus minerals plus fatty acids. Such high correct classification rates demonstrate the robustness of the developed statistical model.

The Effect of Whey on Performance, Gut Health and Bone Morphology Parameters in Broiler Chicks.

Whey is a highly nutritious byproduct of the cheese industry that can be used effectively in the animal feed industry. However, the use of whey in poultry diets is limited by its high lactose and mineral contents. The objective of the present study was to evaluate the effect of different concentrations of whey in poultry diets on the performance, intestinal microbiota and physico-chemical parameters of the intestinal ecosystem, as well as on the bone morphology and its strength in broiler chicks. One hundred and twenty-eight, day-old, male broiler chicks were randomly allocated into four treatment groups of 32 chicks each. The treatment groups were: group A, which served as negative control and groups B, C and D, supplemented with 1, 2 and 5% of dietary whey, respectively. Performance of the groups was evaluated throughout the experiment. Following necropsies, the gastrointestinal tract from each bird was removed, divided into its anatomical parts and intestinal samples were taken for microbiological analysis and for pH and viscosity measurement as well. Tibiotarsus was also collected for morphometric analysis and strength evaluation. The statistical analysis of the experimental data revealed that the dietary supplementation of 1 and 2% of whey improved significantly (p ≤ 0.05) the body weight, while the addition of 5% of whey reduced significantly (p ≤ 0.05) the body weight. Furthermore, the addition of 1, 2 and 5% of dietary whey increased significantly (p ≤ 0.05) the pH of jejunum digesta and reduced significantly (p ≤ 0.05) the pH of caecum digesta compared to the control group. The addition of 1 and 2% of whey reduced significantly (p ≤ 0.05) the viscosity in the jejunum and ileum digesta, compared to the addition of 5% of whey which reduced significantly (p ≤ 0.05) the viscosity in jejunum digesta but increased significantly (p ≤ 0.05) the viscosity in ileum digesta. Moreover, the addition of 1, 2 and 5% of dietary whey increased significantly (p ≤ 0.05) the caecal counts of Lactobacillus spp. and Lactococcus lactis, while the addition of 5% of whey reduced significantly (p ≤ 0.05) the tibiotarsus length. It can be concluded that the addition of low quantities of whey up to 2% promoted the performance and gut health of birds, while the addition of higher quantities of whey at the level of 5% had a detrimental effect on the performance and tibiotarsus length.

Effect of different inoculation strategies of selected yeast and LAB cultures on Conservolea and Kalamàta table olives considering phenol content, texture, and sensory attributes.

BACKGROUND: The effects were studied of different inoculation strategies for selected starters -yeasts and lactic acid bacteria (LAB) - used for the fermentation process of two Greek olive cultivars, Conservolea and Kalamàta. The LAB strains applied were Leuconostoc mesenteroides K T5-1 and L. plantarum A 135-5; the selected yeast strains were S. cerevisiae KI 30-16 and Debaryomyces hansenii A 15-44 for Kalamàta and Conservolea olives, respectively. RESULTS: Table olive fermentation processes were monitored by performing microbiological analyses, and by monitoring changes in pH, titratable acidity and salinity, sugar consumption, and the evolution of volatile compounds. Structural modifications occurring in phenolic compounds of brine were investigated during the fermentation using liquid chromatography / diode array detection / electrospray ion trap tandem mass spectrometry (LC/DAD/ESI-MSn ) and quantified by high-performance liquid chromatography (HPLC) using a diode array detector. Phenolic compounds in processed Kalamàta olive brines consisted of phenolic acids, verbascoside, caffeoyl-6-secologanoside, comselogoside, and the dialdehydic form of decarboxymethylelenolic acid linked to hydroxytyrosol, whereas oleoside and oleoside 11-methyl ester were identified only in Conservolea olive brines. CONCLUSION: Volatile profile and sensory evaluation revealed that the 'MIX' (co-inoculum of yeast and LAB strain) inoculation strategy led to the most aromatic and acceptable Kalamàta olives. For the Conservolea table olives, the 'YL' treatment gave the most aromatic and the overall most acceptable product. © 2019 Society of Chemical Industry.

Physicochemical, Spectroscopic and Chromatographic Analyses in Combination with Chemometrics for the Discrimination of Four Sweet Cherry Cultivars Grown in Northern Greece.

A total of 56 sweet cherry samples belonging to four cultivars (Ferrovia, Canada Giant, Lapins, and Germersdorfer) grown in northern Greece were characterized and differentiated according to botanical origin. For the above purpose, the following parameters were determined: conventional quality parameters (titratable acidity (TA), pH, total soluble solids (TSS), total phenolic content (TPC), mechanical properties and sensory evaluation, sugars by High Performance Liquid Chromatography (HPLC), volatile compounds by GC/MS, and minerals by ICP-OES. Statistical treatment of the data was carried out using Multivariate Analysis of Variance (MANOVA) and Linear Discriminant Analysis (LDA). The results showed that the combination of volatile compounds and conventional quality parameters provided a correct classification rate of 84.1%, the combination of minerals and conventional quality parameters 86.4%, and the combination of minerals, conventional quality parameters and sugars provided the highest correct classification rate of 88.6%. When the above four cherry cultivars were combined with previously studied Kordia, Regina, Skeena and Mpakirtzeika cultivars, collected from the same regions during the same seasons, the respective values for the differentiation of all eight cultivars were: 85.5% for the combination of conventional quality parameters, volatiles and minerals; and 91.3% for the combination of conventional quality parameters, volatiles, minerals, and sugars.

Valorization of Prickly Pear Juice Geographical Origin Based on Mineral and Volatile Compound Contents Using LDA.

In the present work the mineral content and volatile profile of prickly pear juice prepared from wild cultivars was investigated. Fruits used in the study originated from three areas of the Peloponnese Peninsula. Twenty-five macro- and micro-minerals (K, Na, P, Ca, Mg, Al, B, Ba, Be, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Sb, Se, Si, Sn, Ti, Tl, V, Zn) were determined using inductively coupled plasma atomic emission spectroscopy (ICP-OES). Furthermore, analysis of the mineral content of soil samples with ICP-OES showed a perfect correlation with those of fruit juices. Volatile compounds (alcohols, aldehydes, hydrocarbons, terpenoids, and others) were identified using an optimized headspace solid phase microextraction coupled to gas chromatography mass spectrometry (HS-SPME/GC-MS) method. Multivariate analysis showed significant differences (p < 0.05) among the investigated parameters with respect to juice geographical origin. Prickly pear juice samples were classified according to geographical origin by 85.7% and 88.9% using 7 minerals and 21 volatile compounds, respectively.

Inhibitory activity of propolis against Listeria monocytogenes in milk stored under refrigeration.

Propolis is a natural bee-product with documented antimicrobial properties in vitro. The objective of this study was to develop a protocol for adding propolis into milk and to determine whether the addition of propolis can confer anti-listerial activity during the storage of milk under optimal or improper refrigeration conditions. Upon dissolving propolis ethanolic extract (PEE) into glycerol, the PEE-glycerol mixture contained no visible insoluble particles and could be dispersed evenly into milk, without leaving any insoluble material. PEE, with or without glycerol, was added into extended shelf-life milk, artificially contaminated with Listeria monocytogenes. The addition of PEE dissolved into glycerol resulted in a pronounced and dose-dependent anti-listerial effect in milk stored at 4 °C, with the higher concentration tested (4 mg of dry PEE per mL of milk) resulting in complete inhibition of L. monocytogenes growth throughout 30 days of storage. The combination of PEE with glycerol was also effective in significantly reducing the growth rate of the pathogen in milk stored under improper refrigeration (10 °C). Based on a patented PEE-deodorization protocol, the addition of deodorized PEE into milk resulted in a product with average consumer acceptability. However, the PEE deodorization process resulted in reduction or even complete removal of propolis constituents with known antibacterial activity, with a concomitant significant reduction in its anti-listerial effect. Nonetheless, the data presented in this manuscript highlight the strong anti-listerial potential of propolis in milk and suggest that, upon further research on its deodorization and standardization, there may be room for the application of propolis as a natural preservative in dairy beverages.

Characterization and differentiation of sheep's milk from Greek breeds based on physicochemical parameters, fatty acid composition and volatile profile.

BACKGROUND: There are only limited studies in the literature attempting to differentiate sheep's milk originating from different sheep breeds. In the present study the physicochemical parameters (pH, percent fat, percent protein, percent lactose and percent total solids), fatty acid composition and volatile profile of raw milk from four autochthonous Greek breeds (Karagouniko, Mpoutsiko, Artas and Chios) were determined. The objective of the present study was to characterize and differentiate the sheep breeds based on the above analytical parameters in combination with chemometrics. RESULTS: The overall correct classification rate was 79.7%%, 84.4% and 100% based on physicochemical parameters, fatty acid composition and volatile profile, respectively. Volatiles proved to be the most effective of parameters analyzed for the differentiation of sheep breed. Furthermore, the combination of physicochemical parameters and fatty acid composition gave a correct classification rate equal to 96.9%. CONCLUSION: Either volatile profile or the combination of physicochemical parameters and fatty acid composition may be easily determined and used for the differentiation of sheep's milk from four different Greek breeds, this being the novelty of the present work. This may be very important in terms of PDO (Protected Designation of Origin) and PGI (Protected Geographical Indication) products related to specific geographical origin and sensory characteristics. © 2018 Society of Chemical Industry.