Comparative Effect of Bunium persicum and Rosmarinus officinalis Essential Oils and Their Synergy with Citric Acid on the Oxidation of Virgin Olive Oil

The objective of this study was to evaluate the effect of Bunium persicum and Rosmarinus officinalis essential oils on the oxidation of virgin olive oil during accelerated storage. The synergistic effect between citric acid and antioxidants of natural and synthetic types was investigated. The B. persicum and R. officinalis essential oils significantly retarded the oxidation of virgin olive oil. Their antioxidant capacity was comparable to butylatedhydroxytoluene and better than β-carotene. Here we show that when natural and synthetic antioxidants are combined with citric acid, they produce an extra antioxidant effect, hence the manifestation of synergy. Generally, the essential oils of B. persicum and R. officinalis can be applied to increase the oxidative stability of virgin olive oil.     

Membrane‐Filtered Olive Mill Wastewater: Quality Assessment of the Dried Phenolic‐Rich Fraction

A current trend in olive mill wastewater (OMWW) management is to not only decrease environmental pollution but also to extract and utilize valuable by‐products. Therefore, the objectives of this study were to explore different techniques for drying a phenolic‐rich membrane filtration fraction of OMWW and compare the techniques in terms of the dried product quality and feasibility of the process. The OMWW from 2 (3‐phase and 2‐phase) California mills was subjected to a 2‐step membrane filtration process using a novel vibratory system. The reverse osmosis retentate (RO‐R) is a phenolic‐rich coproduct stream, and the reverse osmosis permeate is a near‐pure water stream that could be recycled into the milling process. Spray‐, freeze‐, and infrared‐drying were applied to obtain solid material from the RO‐R. Drying of the RO‐R was made possible only with addition of 10% maltodextrin as a carrier. The total soluble phenolics in dried RO‐R were in the range 0.15 to 0.58 mg gallic acid equivalents/g of dry weight for 2‐phase RO‐R, and 1.38 to 2.17 mg gallic acid equivalents/g of dry weight for the 3‐phase RO‐R. Spray‐dried RO‐R from 3‐phase OMWW showed remarkable antioxidant activity. Protocatechuic acid, tyrosol, vanillic acid, and p‐coumaric acid were quantified in all dried RO‐R, whereas 3‐hydroxytyrosol was found in 3‐phase dried RO‐R. This combination of separation and drying technologies helps to add value and shelf‐stability to an olive oil by‐product and increase environmental sustainability of its production.     

Ripened Semihard Cheese Covered with Lard and Dehydrated Rosemary (Rosmarinus officinalis L.) Leaves: Processing,Characterization, and Quality Traits

This study aimed to establish a manufacturing protocol and to characterize semihard cheese covered with lard and rosemary during ripening. After the manufacturing protocol was defined, the cheeses were produced with pasteurized and raw milk from Holstein cows, with and without (control) coating, and then ripened for 60 d. During this period the physicochemical properties, color, proteolysis, texture profile, and sensory acceptance were performed. The early‐ripening cheeses differed from the others in terms of color and moisture content. Multivariate statistical analysis separated chesses in groups differentiated by the effects of heat treatment of milk and ripening period. The ripened cheeses obtained from raw milk were sensorially more preferred. The coating gave the final products higher moisture content and favored color and texture characteristics. Consumer testing showed that the cheese obtained from raw milk and coated with lard and rosemary was the most preferred (acceptance of 82%) due to the specific coating of rosemary (aroma and flavor). This product has potential to add value and to diversify the production of semihard cheeses.     

Tolerance evaluation in Salmonella enterica serovar Typhimurium challenged with sublethal amounts of Rosmarinus officinalis L. essential oil or 1,8‐cineole in meat model

The induction of direct bacterial tolerance and cross‐tolerance (NaCl, acid pH, high temperature) in Salmonella Typhimurium ATTC 14028 following the exposure to sublethal amounts of the essential oil from Rosmarinus officinalis L. (ROEO), and its major component 1,8‐cineole (CIN) was evaluated in this study. Direct protection was not induced when cells were exposed to 1/2 MIC and 1/4 MIC of ROEO or CIN in meat broth and in previously irradiated meat ground‐beef. Cells exposed to ROEO or CIN at sublethal amounts did not present cross‐protection to high temperature, lactic acid and NaCl. Likewise, cells progressively subcultured in meat broth containing increasing amounts of ROEO or CIN were able to survive only up to 1/4 MIC for both tested substances. From these results, S. Typhimurium ATCC 14028 was not capable to develop direct or cross‐tolerance when exposed to ROEO or CIN in a meat‐based growth media and was not able to develop direct tolerance in a meat‐based model.     

A multivariate approach to optimise the synergistic blend of oleoresin rosemary (Rosmarinus officinalis L.) and ascorbyl palmitate added into sunflower oil

The simultaneous optimisation of a synergistic blend of oleoresin rosemary (ROS) and ascorbyl palmitate (AP) in sunflower oil (SO) was performed using central composite and rotatable design coupled with principal component analysis (PCA) and response surface methodology (RSM). The physicochemical parameters, viz. peroxide value, anisidine value, induction period, total polar matter, UV absorbances (232 and 270 nm) and antioxidant capacity were considered as response variables. PCA reduced the original set of correlated responses to few uncorrelated principal components (PC). The PC1 (eigenvalue, 6.08; data variance explained, 86.97%) was selected for optimisation using RSM. The quadratic model described the data (R² = 0. 93, P < 0.05), and lack of fit was insignificant (P > 0.05). The contour plot of PC 1 score indicated the optimal synergistic combination of 1309.62 and 129.29 ppm for ROS and AP, respectively. In conclusion, the versatility of PCA–RSM approach has resulted in an easy interpretation in multiple response optimisations.     

Assessment of chemically characterised Rosmarinus officinalis L. essential oil and its major compounds as plant‐based preservative in food system based on their efficacy against food‐borne moulds and aflatoxin secretion and as antioxidant

The study explores antifungal, anti‐aflatoxigenic and antioxidant efficacy of Rosmarinus officinalis essential oil (ROEO) and its major compounds. In addition, the mode of action of ROEO and its practical efficacy as preservative have been assessed. GC‐MS analysis of ROEO identified 16 compounds; α‐pinene, 1,8‐cineole and camphor being the major compounds. The minimum concentration for inhibition of growth and aflatoxin B₁ secretion against A. flavus (LHP‐6) was found to be 1.5, >5.0, 4.0 and 3.0 μL mL^?1 and 1.25, >5.0, 3.5 and 3.0 μL mL^?1 for ROEO, α‐pinene, 1,8‐cineole and camphor, respectively. The IC₅₀ value through DPPH analysis and percentage inhibition of linoleic acid peroxidation of ROEO were 0.042 μL mL^?1 and 71.05%, respectively. The targeted site of antifungal action of ROEO was confirmed as plasma membrane through ergosterol measurement and TEM analysis. Moreover, ROEO significantly protected Piper nigrum fruits against mould infestation upto 6 months in in vivo trial.