Characterization, Sensory and Oxidative Stability Analysis of Vegetable Mayonnaise Formulated with Olive Leaf Vinegar as an Active Ingredient.

Development of novel food products represents a basic meeting point for health and business requirements. Mayonnaise sauce is well-suited to be a healthy and tasty dressing. In this study, mayonnaise was formulated by using unconventional ingredients, such as olive leaf vinegar (OLV), soybean/high oleic sunflower oil blend, and soymilk (as an egg substitute). An 18% alcoholic vinegar was used as the control sample. OLV is a rich source of bioactive substances, especially polyphenols and represents a possible way to enhance the olive oil by-product valorisation. For this new typology of vinegar an high level of phenolic compounds (7.2 mg/mL GAE), especially oleuropein (6.0 mg/mL oleuropein equivalent) was found. OLV mayonnaise had 57% fat, composed of 11%, 64%, and 23% saturated, monounsaturated, and polyunsaturated fatty acids, while linolenic acid was up to 1.7%. The phenol and oleuropein contents were 68 and 52 mg/100 g, respectively. Sensory panellists expressed a moderate overall acceptability for both samples but attested more distinctive and positive sensations for the colour, odour, and taste attributes of OLV mayonnaise. Finally, oxidative stability and shelf life were better in OLV mayonnaise than in the control. Specifically, the peroxide value remained low (around 4.5 meqO2/kg) after 12 months of storage at room and low (4 °C) temperatures.

Progress in Colloid Delivery Systems for Protection and Delivery of Phenolic Bioactive Compounds: Two Study Cases-Hydroxytyrosol and Curcumin.

Insufficient intake of beneficial food components into the human body is a major issue for many people. Among the strategies proposed to overcome this complication, colloid systems have been proven to offer successful solutions in many cases. The scientific community agrees that the production of colloid delivery systems is a good way to adequately protect and deliver nutritional components. In this review, we present the recent advances on bioactive phenolic compounds delivery mediated by colloid systems. As we are aware that this field is constantly evolving, we have focused our attention on the progress made in recent years in this specific field. To achieve this goal, structural and dynamic aspects of different colloid delivery systems, and the various interactions with two bioactive constituents, are presented and discussed. The choice of the appropriate delivery system for a given molecule depends on whether the drug is incorporated in an aqueous or hydrophobic environment. With this in mind, the aim of this evaluation was focused on two case studies, one representative of hydrophobic phenolic compounds and the other of hydrophilic ones. In particular, hydroxytyrosol was selected as a bioactive phenol with a hydrophilic character, while curcumin was selected as typical representative hydrophobic molecules.

Effective assay for olive vinegar production from olive oil mill wastewaters.

In this work, an effective and simple approach for vinegar production from olive oil press-mill wastewaters (OMW) is presented. Effects of sterilization and yeast presence on the acetic acid production were investigated. Sugar addition and inoculum of selected yeast starter have been crucial for a satisfactory acidification. In the obtained olive vinegar, the pH and total acidity were 2.92 and 5.6%, respectively. A considerable high level of ash (2%) and total phenols (3600mg/L as GAE) characterized olive vinegar, in comparison with samples of apple, wine and balsamic commercial vinegars. Moreover, a high presence of hydroxytyrosol (1019mg/L) was obtained. This abundant presence of antioxidants makes olive vinegar a promising nutraceutical and environmentally-friendly product, based upon a waste material such as OMW.

Technological Potential of Lactobacillus Strains Isolated from Fermented Green Olives: In Vitro Studies with Emphasis on Oleuropein-Degrading Capability.

Technological properties of two strains of Lactobacillus plantarum (B3 and B11) and one of Lactobacillus pentosus (B4), previously isolated from natural fermented green olives, have been studied in vitro. Acidifying ability, salt, temperature, and pH tolerances of all strains were found in the range reported for similar strains produced in Italy and optimal growth conditions were found to be 6.0-8.0 pH, 15-30°C temperature, and less than 6% NaCl. Moreover, all strains showed very good tolerance to common olive phenol content (0.3% total phenol) and high oleuropein-degrading capability. It was found that medium composition affected the bacterial oleuropein degradation. B11 strain grown in a nutrient-rich medium showed a lower oleuropein-degrading action than when it was cultivated in nutrient-poor medium. Furthermore, enzymatic activity assays revealed that oleuropein depletion did not correspond to an increase of hydroxytyrosol, evidencing that bacterial strains could efficiently degrade oleuropein via a mechanism different from hydrolysis.

Evidence of oleuropein degradation by olive leaf protein extract.

The enzymatic activity of raw protein olive leaf extract has been investigated in vivo, on olive leaf homogenate and, in vitro with pure oleuropein and other phenolic substrates. At least two types of enzymes were found to be involved in the degradation of endogenous oleuropein in olive leaves. As for the in vitro experiments, the presence of active polyphenoloxidase and ß-glucosidase was determined by HPLC and UV-Visible spectroscopy. Interestingly, both the enzymatic activities were found to change during the storage of olive leaves. Specifically, the protein extracts obtained from fresh leaves showed the presence of both the enzymatic activities, because oleuropein depletion occurred simultaneously with the formation of the oleuropein aglycon, 3,4-DHPEA-EA. In comparison leaves subjected to the drying process showed a polyphenoloxidase activity leading exclusively to the formation of oxidation products responsible for the typical brown coloration of the reaction solution.

Yeast Autolysis in Sparkling Wine Aging: Use of Killer and Sensitive Saccharomyces cerevisiae Strains in Co-Culture.

BACKGROUND: Sparkling wines produced by traditional method owe their characteristics to secondary fermentation and maturation that occur during a slow ageing in bottles. Yeast autolysis plays an important role during the sparkling wine aging. Using a combination of killer and sensitive yeasts is possible to accelerate yeast autolysis and reduce maturing time. METHODS: killer and sensitive Saccharomyces cerevisiae strains, separately and in co-cultures, were inoculated in base wine and bottled on pilot-plant scale. Commercial Saccaromyces bayanus strain was also investigated. Protein free amino acid and polysaccharides contents and sensory analysis were determined on the wine samples at 3, 6 and 9 months of aging. Yeast autolysis that occurs during the production of sparkling wines, obtained with co-cultures of killer and sensitive strains, has influenced free amino acids, total protein and polysaccharides content after 3 months aging time: sparkling wines, produced without the use of these yeasts, have reached the same results only after 9 months aging time. RESULTS: These results demonstrate that killer and sensitive yeasts in co-culture can accelerate the onset of autolysis in enological conditions, and has a positive effect on the quality of the aroma and flavor of sparkling wine. CONCLUSION: This paper offers an interesting biotechnological method to reduce production time of sparkling wine with economical benefits for the producers. We revised all patents relating to sparkling wine considering only those of interest for our study.

The role of microemulsions in lipase-catalyzed hydrolysis reactions.

The kinetics of the p-nitrophenyl butyrate hydrolysis reaction, catalyzed by Candida rugosa lipase in the water-in-oil microemulsion cetyltrimethylammonium bromide/water/pentanol/hexane, was investigated. The results described in the present manuscript reveal two peculiar characteristics of the reaction: (i) the initial rate of hydrolysis is very fast and (ii) by decreasing the water content of the microemulsion, the reaction rate approaches the typical behavior of reactions performed in aqueous solution. In particular, for microemulsion systems with a high water content, the end points of the reactions are dictated by the shape stability of the microemulsion. For these systems, our methodological approach shows that the process follows a second-order kinetics equation, indicative of the dual role played by water, which is involved both as a component of the microemulsion, i.e., relevant for the microemulsion stability and as a reagent of the hydrolysis reaction. In contrast, for microemulsions containing a small amount of water, after the hydrolysis reaction the system seems to fall in the no existence range of the microemulsion. Accordingly, the kinetics results are more complex: in the initial stage, the reaction follows a zero-order kinetics equation, while for longer reaction times a first-order kinetics equation fits the experimental data, as would be expected for an enzymatic reaction in a homogeneous system.

Heat-oxidation stability of palm oil blended with extra virgin olive oil.

Rancimat induction time of palm oil (PO), several extra virgin olive oils (EV) and their binary blends have been determined at three different temperatures (120, 130 and 140°C). Analytical composition and oxidation stability of PO/EV blends were found to be a linear combination of the oil partners. Induction time of pure PO was always higher than those of EV oils and blends, in which induction time increased proportionally with the percentage of PO. However, induction time of 80% PO blend was similar to that of pure PO. Fatty acid composition appeared to be the most important factor affecting heat-oxidation stability and a saturated/unsaturated ratio near 1 was the optimally stable composition. Conversely, total phenols had a zero or negative role on the oxidative stability of the blends. Finally, in heat-oxidised oils significant losses of polyunsaturated fatty acids and formation of short-chain fatty acids were recorded.

A study on the lipid fraction of Adriatic sardine filets (Sardina pilchardus).

Sardine (Sardina pilchardus Walb.) is an important Mediterranean commercial fish species. In this study, the lipids of sardine filets, fished in the Adriatic Sea at different times, were examined. In function of their total lipid (TL) content, sardine filet samples were grouped into lean (TL < 4%) and fat (TL > 4%). It was demonstrated that the differences of TL were exclusively due to a seasonal cyclical increase of neutral lipids. In fact, during moderate-hot months, sardines accumulated reserve fat that was metabolised during the winter months. The fatty acid composition was similar in both sardine sample groups and the fatty acid profile was equally distributed among saturated fatty acids, on average 38.3%, 31.2% monounsaturated, and 30.4% polyunsaturated. The polyunsaturated fatty acid n3 (PUFA-n3) represented on average 20.9%, always higher than PUFA-n6. C20:5n3 eicosapentaenoic acid, (EPA) and C22:6n3 docosahexaenoic acid (DHA) were the must abundant PUFA-n3. Under nutritional aspects, the lipids of 100 g of fat-sardines provided PUFA-n3 quantities, in particular EPA and DHA, significantly higher than human daily requirements. In lean-sardines, the PUFA-n3 input drastically decreased and was estimated that EPA and DHA inputs in 100 g of sardines covered around 17% and 50% of daily requirements, respectively. Finally, cholesterol was equal to 93 mg/100 g of sardines, ranging from 67 to 131 and it did not increase in relation to the total lipid content. In conclusion, this study has highlighted that, under nutritional aspects, regarding EPA and DHA inputs, it is preferable to consume sardines with at least 4% total lipids.