Food Science and Nutrition

Olive paste may exert bioactivity due to its richness in bioactive components, such as oleic acid and polyphenols. The present interventional human study investigated if the fortification of cookies with olive paste and herbs may affect postprandial lipemia, oxidative stress, and other biomarkers in healthy volunteers. In a cross-over design, 10 healthy volunteers aged 20–30 years, consumed a meal, rich in fat and carbohydrates (50 g cookies). After a washout week, the same volunteers consumed the same cookie meal, enhanced with 20% olive paste. Blood sampling was performed before, 0.5 h, 1.5 h, and 3 h after eating. Total plasma antioxidant capacity according to FRAP, ABTS, and resistance to copper-induced plasma oxidation, serum lipids, glucose, uric acid, and antithrombotic activity in platelet-rich plasma were determined at each timepoint. There was a significant decrease in triglycerides’ concentration in the last 1.5 h in the intervention compared to the control group (p < ...

Postprandial lipemia, glycemia and oxidative stress may affect the occurrence of cardiovascular disease. The purpose of the present intervention study was to investigate the effect of a spread cheese enriched with mountain tea (Sideritis sp.) and orange peel (Citrus sinensis) extract on postprandial metabolic biomarkers in healthy volunteers. In a cross-over design, 14 healthy subjects 20–30 years old were consumed either a meal rich in fat and carbohydrates (80 g white bread, 40 g butter and 30 g full fat spread cheese) or a meal with the spread cheese enriched with 6% mountain tea–orange peel extract. Differences in postprandial total plasma antioxidant capacity, resistance of plasma to oxidation, serum lipids, glucose and uric acid levels were evaluated at 0, 1.5 and 3 h after consumption. Plasma total antioxidant capacity was significantly increased 3 h after the consumption of the meal in the presence of the extract-enriched cheese, compared to the conventional cheese (p = 0.05...

Olive paste may exert bioactivity due to its richness in bioactive components, such as oleic acid and polyphenols. The present interventional human study investigated if the fortification of cookies with olive paste and herbs may affect postprandial lipemia, oxidative stress, and other biomarkers in healthy volunteers. In a cross-over design, 10 healthy volunteers aged 20–30 years, consumed a meal, rich in fat and carbohydrates (50 g cookies). After a washout week, the same volunteers consumed the same cookie meal, enhanced with 20% olive paste. Blood sampling was performed before, 0.5 h, 1.5 h, and 3 h after eating. Total plasma antioxidant capacity according to FRAP, ABTS, and resistance to copper-induced plasma oxidation, serum lipids, glucose, uric acid, and antithrombotic activity in platelet-rich plasma were determined at each timepoint. There was a significant decrease in triglycerides’ concentration in the last 1.5 h in the intervention compared to the control group (p < ...

Several fruit by-products may exert a beneficial role on oxidative stress and inflammation modulation, providing essential bioactive components, such as polyphenols and carotenoids. Recently, the potential bioactivity of miso has been reported. The aim of this dietary intervention–clinical study was to evaluate the acute effect of a novel, functional miso-type sauce based on legumes, on postprandial biomarkers of oxidative stress and inflammation. In this randomized, cross-over design, intervention–clinical trial, 14 healthy volunteers, aged 20–30 years old, consumed a rice meal rich in fat and carbohydrates (258 g), containing a legume-based sauce. After a 1-week washout period, the same subjects consumed the same meal, containing the novel fermented miso-type sauce, enhanced with 50% carotenoid-rich, fruit peel extract. Differences in postprandial total plasma antioxidant capacity according to the FRAP method, serum lipids, glucose, uric acid levels, and antithrombotic activity in...

Postprandial lipemia, glycemia and oxidative stress may affect the occurrence of cardiovascular disease. The purpose of the present intervention study was to investigate the effect of a spread cheese enriched with mountain tea (Sideritis sp.) and orange peel (Citrus sinensis) extract on postprandial metabolic biomarkers in healthy volunteers. In a cross-over design, 14 healthy subjects 20–30 years old were consumed either a meal rich in fat and carbohydrates (80 g white bread, 40 g butter and 30 g full fat spread cheese) or a meal with the spread cheese enriched with 6% mountain tea–orange peel extract. Differences in postprandial total plasma antioxidant capacity, resistance of plasma to oxidation, serum lipids, glucose and uric acid levels were evaluated at 0, 1.5 and 3 h after consumption. Plasma total antioxidant capacity was significantly increased 3 h after the consumption of the meal in the presence of the extract-enriched cheese, compared to the conventional cheese (p = 0.05...

Several Mediterranean functional foods and their process by-products may exert a beneficial role on hyperlipidemia, hyperglycemia, and oxidative stress modulation, providing bioactive compounds with functional properties, contributing to possible chronic disease prevention (cardiovascular disease, metabolic syndrome, obesity, diabetes mellitus, etc.). The purpose of the present interventional study was to investigate the postprandial responses of metabolic biomarkers, after the intake of an innovative mayonnaise-based appetizer, enhanced with olive paste, in healthy volunteers. In this cross-over design, randomized and single-blind, interventional–clinical trial, 10 healthy volunteers, aged 20–30 years old, after splitting into the control group and the Mediterranean group, consumed a pasta meal rich in fat and carbohydrates (150 g), containing a mayonnaise-based appetizer or the same appetizer, enhanced with 9% olive paste. After a 1-week washout period, the subjects consumed the m...

Several Mediterranean traditional cheeses may present a beneficial effect on postprandial metabolic and inflammatory modulation due to the presence of bioactive components. The objective of the present preliminary nutritional intervention was the investigation of the postprandial metabolic responses after the intake of traditional Authentic Mytilinis cheese in olive oil with herbs, compared to the corresponding responses after consumption of Italian Parmesan cheese, in healthy participants. A pilot crossover, randomized, single-blinded, intervention clinical trial was conducted in 10 healthy men and women subjects, aged 18–30 years, after random allocation into the control and the intervention groups. The participants received a high-fat carbohydrate meal containing either Authentic Mytilinis cheese (the authentic nonrefrigerated recipe) or Italian Parmesan PDO cheese. After a washout week, the participants consumed the same meals conversely. Differences in the postprandial response...

Wheat-flour crackers represent a staple snack option, although they lack nutritional value. Agricultural by-products such as olive and grape seeds, cereals such as barley and legumes such as lupine and chickpea are rich in bioactive compounds; therefore, flours obtained from those could represent a better option for bakery products fortification. The purpose of the present study was the investigation of total phenolic content and antioxidant activity before and after the baking of wheat crackers enriched with 10–30% olive seed, 10–30% grape seed, 10–40% lupine, 10–30% barley and 20–60% and 80% chickpea flours and the evaluation of the predicted bioavailability after in vitro digestion of crackers demonstrating the highest values. Crackers and doughs were processed and analyzed using Folin–Ciocâlteu and ferric reducing antioxidant power (FRAP) assays, respectively. Crackers with the highest properties were subjected to in vitro gastrointestinal digestion. Baking resulted in an increa...

Nowadays, there is a high demand in many industrial countries for healthy foods and sustainable products and so to explore innovative food technologies, such as fortification with bioactive compounds such as antioxidants and polyphenols, that may be sourced from herbs or by-products. This study’s objective was to explore the fortification of refined olive oils with natural bioactive compounds such as the herbs rosemary (Rosmarinus officinallis, L.), basil (Ocimum basillicum, L.), sage (Salvia officinalis, L.), lemon balm (Melissa oficinallis, L.), St. John’s wort (Hypericum perforatum, L.), pink savory (Satureja thymbra, L.), dittany (Origanum dictamnus, L.), and by-products such as pomace from olives, olive leaves (Olea europaea, L.), orange peel (Citrus aurantium, L.), lemon peel (Citrus limon, L.), pomegranate peel (Punica granatum, L.), and mandarin peel (Citrus reticulata). The fortification of the refined olive oils was performed with the use of different methodologies such as...

Background: Obesity persists as a significant public health concern. Recent novel strategies advocate for the incorporation of specific foods to better manage adiposity markers and prevent obesity. Numerous epidemiological and clinical studies highlight the potential benefits of including natural functional foods from the Mediterranean Diet, as well as processed foods enhanced with bioactive compounds. Methods: A validated Functional Food Frequency of Consumption (FFFQ) was administered in 319 Greeks and Cypriots volunteers, aged 18-75. Anthropometric and body composition measures were recorded through established protocols. Linear regression models were used to examine the association between frequency intake of foods and adiposity markers. Objective: This study was designed to investigate the potential relationship between the frequency of selective foods and obesity markers, among Greek and Cypriot adults. Results: In this study, 33 natural (i.e., fruits, vegetables, pulses, starchy food items, herbs and spices, beverages, other) and processed (i.e., starchy food items, dairy, fats and oils) functional foods were considered. Most of the foods are consumed weekly/ monthly, whilst participants report daily consumption of olive oil (57%) and coffee (61%). Monthly intake of whole wheat cereals, herbs (thyme/ oregano/ basil), and nuts were associated with greater BMI, at the Bonferroni correction level (p=0.0004). However, results from multiple regression models adjusted for sex, age group, educational level, smoking status, physical activity status, and water intake revealed that only monthly nut intake, compared to daily intake, was associated with greater BMI (2.9 (1.5; 4.4) kg/m2). The results suggest that the infrequent intake of nuts on Greek and Cypriot participants, is a strong determinant of BMI, and the rare consumption of whole wheat cereals and herbs (thyme/oregano/basil) may weakly affect BMI. Further research is required to safely conclude to these claims, and the implementation of nutritional education programs on functional foods may prove effective in the prevention and management of obesity.

Background: Grape seed polyphenol bioactivity is linked to reduced risk of metabolic syndrome, type 2 diabetes, obesity, and coronary heart disease development. Furthermore, regular consumption of β-glucan is associated with decreased lipidemic and glycemic profiles. The aim was to investigate the acute effect of crackers enriched with either 10% grape seed flour or 40% barley flour with added β-glucan along with a high-fat and high-carbohydrate meal on biomarkers of postprandial glycemia, lipidemia, and oxidative stress. Methods: In a randomized, three-arm crossover design study, 12 healthy subjects were assigned to consume breakfast consisting of bread, butter, and 250 mL water along with crackers containing either (a) wheat flour, (b) 10% grape seed flour, or (c) 40% barley flour enriched with β-glucan. Blood samples were drawn immediately before and 30, 90, and 180 min after the meal. Total antioxidant capacity was measured in plasma with the FRAP method. Total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, glucose, and uric acid were measured in serum. Results: Tested markers did not differ between the intervention groups at baseline, 30, 90, and 180 min (p ≥ 0.05) post-prandially. Conclusions: Enriched cracker consumption did not significantly affect the selected markers at the postprandial state, although better serum glucose and lipid levels, similar to baseline values, were maintained.

The presence of pathogens in dairy products is often associated with contamination via bacteria attached to food-processing equipment, especially from areas where cleaning/sanitation is difficult. In this study, the attachment of Listeria monocytogenes on stainless steel (SS), followed by detachment and growth in foods, was evaluated under conditions simulating a dairy processing environment. Initially, SS coupons were immersed in milk, vanilla custard, and yogurt inoculated with the pathogen (10 7 CFU/ml or CFU/g) and incubated at two temperatures (5 and 20°C) for 7 days. By the end of incubation, cells were mechanically detached from coupons and used to inoculate freshly pasteurized milk which was subsequently stored at 5°C for 20 days. The suspended cells in all three products in which SS coupons were immersed were also used to inoculate freshly pasteurized milk (5°C for 20 days). When SS coupons were immersed in milk, shorter lag phases were obtained for detached than for planktonically grown cells, regardless of the preincubation temperature (5 or 20°C). The opposite was observed when custard incubated at 20°C was used to prepare the two types of inocula. However, in this case, a significant increase in growth rate was also evident when the inoculum was derived from detached cells. In another parallel study, while L. monocytogenes was not detectable on SS coupons after 7 days of incubation (at 5°C) in inoculated yogurt, marked detachment and growth were observed when these coupons were subsequently transferred and incubated at 5°C in fresh milk or/and custard. Overall, the results obtained extend our knowledge on the risk related to contamination of dairy products with detached L. monocytogenes cells.

This study aimed to investigate the possible influence of bacterial intra-and interspecies interactions on the ability of Listeria monocytogenes and Salmonella enterica to develop mixed-culture biofilms on an abiotic substratum, as well as on the subsequent resistance of sessile cells to chemical disinfection. Initially, three strains from each species were selected and left to attach and form biofilms on stainless steel (SS) coupons incubated at 15°C for 144 h, in periodically renewable tryptone soy broth (TSB), under either monoculture or mixed-culture (mono-/dual-species) conditions. Following biofilm formation, mixed-culture sessile communities were subjected to 6-min disinfection treatments with (i) benzalkonium chloride (50 ppm), (ii) sodium hypochlorite (10 ppm), (iii) peracetic acid (10 ppm), and (iv) a mixture of hydrogen peroxide (5 ppm) and peracetic acid (5 ppm). Results revealed that both species reached similar biofilm counts (ca. 10 5 CFU cm ؊2 ) and that, in general, interspecies interactions did not have any significant effect either on the biofilm-forming ability (as this was assessed by agar plating enumeration of the mechanically detached biofilm bacteria) or on the antimicrobial resistance of each individual species. Interestingly, pulsed-field gel electrophoresis (PFGE) analysis clearly showed that the three L. monocytogenes strains did not contribute at the same level either to the formation of mixed-culture sessile communities (mono-/dual species) or to their antimicrobial recalcitrance. Additionally, the simultaneous existence inside the biofilm structure of S. enterica cells seemed to influence the occurrence and resistance pattern of L. monocytogenes strains. In sum, this study highlights the impact of microbial interactions taking place inside a mixed-culture sessile community on both its population dynamics and disinfection resistance.

Biofilm formation on stainless steel by Salmonella enterica serovar Enteritidis PT4 during growth in three different nutritious conditions was studied. The ability of micro-organisms to generate biofilms on the stainless steel surfaces was studied for a total period of 18 days at 20 1C, under three different experimental treatments: (i) growth medium (tryptone soy broth) was not refreshed (no further nutrients were provided) during the incubation period, (ii) growth medium was renewed every 2 days and (iii) growth medium was renewed every 2 days and at the same time the planktonic cells from the old medium were transferred to the new fresh medium. It was found that biofilms developed better and a higher number of adherent cells (ca. 10 7 cfu/cm 2 ) were recovered when the organism was grown in periodically renewed nutrient medium than when the growth medium was not refreshed. Regardless of the availability of nutrients, biofilm development was better (range 2-3 logs greater) when coupons were not totally covered by the growth medium and part of the surface was exposed to the air-liquid interface, than when coupons were submerged in the medium. The results suggest that existence of air-liquid interface and adequate nutrient conditions provide the best environment for Salmonella Enteritidis PT4 biofilm formation on stainless steel. The possible role of stationary phase planktonic cells in biofilm development by sessile/attached microbial cells is also discussed. r

Effect of acid tolerance response (ATR) on attachment of Listeria monocytogenes Scott A to stainless steel under extended exposure to acid or/and salt stress and resistance of sessile cells to subsequent strong acid challenge The aim of this study was to investigate the potential effect of adaptive stationary phase acid tolerance response (ATR) of Listeria monocytogenes Scott A cells on their attachment to stainless steel (SS) under low pH or/and high salt conditions and on the subsequent resistance of sessile cells to strong acid challenge. Nonadapted or acid-adapted stationary-phase L. monocytogenes cells were used to inoculate (ca. 10 8 CFU/ml) Brain Heart (BH) broth (pH 7.4, 0.5% w/v NaCl) in test tubes containing vertically placed SS coupons (used as abiotic substrates for bacterial attachment). Incubation was carried out at 16°C for up to 15 days, without any nutrient refreshment. L. monocytogenes cells, prepared as described above, were also exposed to low pH (4.5; adjusted with HCl) or/and high salt (5.5% w/v NaCl) stresses, during attachment. On the 5th, 10th and 15th day of incubation, cells attached to SS coupons were detached (through bead vortexing) and enumerated (by agar plating). Results revealed that ATR significantly (p b 0.05) affected bacterial attachment, when the latter took place under moderate acidic conditions (pH 4.5, 0.5 or 5.5% w/v NaCl), with the acid-adapted cells adhering slightly more than the nonadapted ones. Regardless of acidity/salinity conditions during attachment, ATR also enhanced the resistance of sessile cells to subsequent lethal acid challenge (exposure to pH 2 for 6 min; pH adjusted with either hydrochloric or lactic acid). The trend observed with viable count data agreed well with conductance measurements, used to indirectly quantify remaining attached bacteria (following the strong acid challenge) via their metabolic activity. To sum, this study demonstrates that acid adaptation of L. monocytogenes cells during their planktonic growth enhances their subsequent attachment to SS under extended exposure (at 16°C for up to 15 days) to mild acidic conditions (pH 4.5), while it also improves the resistance of sessile cells to extreme acid treatment (pH 2). Therefore, the ATR of bacterial cells should be carefully considered when applying acidic decontamination strategies to eradicate L. monocytogenes attached to food processing equipment.

Aims: To assess the antimicrobial action of three natural-derived products (essential oil, decoction and hydrosol of Satureja thymbra) against biofilms, composed of useful, spoilage and pathogenic bacteria (formed as monoculture or ⁄ and mixed-culture), and to compare their efficiency with three standard acid and alkaline chemical disinfectants. Methods and Results: Two acids (hydrochloric and lactic, pH 3), one alkali (sodium hydroxide, pH 11), the essential oil of S. thymbra (1% v ⁄ v) and the two by-products of the essential oil purification procedure (the decoction and the hydrosol fraction of essential oil, 100%), were tested against biofilms formed by five bacterial species, either as monospecies, or as mixed-culture of all species. The tested bacterial species were Staphylococcus simulans and Lactobacillus fermentum (useful technological bacteria), Pseudomonas putida (spoilage bacterium), Salmonella enterica and Listeria monocytogenes (pathogenic bacteria). Biofilms were left to be formed on stainless steel coupons for 5 days at 16°C, before the application of disinfection treatments, for 60 and 180 min. The disinfection efficiency was evaluated by detaching the remaining viable biofilm cells and enumerating them by agar plating, as well as by automated conductance measurements (using Rapid Automated Bacterial Impedance Technique). Both these methods revealed that the essential oil and the hydrosol of S. thymbra exhibited a strong antimicrobial action against both monospecies and mixed-culture biofilms. Surprisingly, the efficiency of the other three acidbase disinfectants was not adequate, although a long antimicrobial treatment was applied (180 min). Conclusions: The essential oil of S. thymbra (1%), as well as its hydrosol fraction (100%), presents sufficient bactericidal effect on bacterial biofilms formed on stainless steel. Significance and Impact of the Study: Use of natural antimicrobial agents could provide alternative or supplemented ways for the disinfection of microbial-contaminated industrial surfaces.