Effect of elaboration process, crop year and irrigation on acrylamide levels of potential table olive varieties.

BACKGROUND: Table olives are widely consumed in the Mediterranean diet, and several typical Spanish and Portuguese varieties could potentially be used as such. In order to ensure a good-quality product, the effect of different factors such as elaboration processes, irrigation conditions, crop year and their crossover interaction on acrylamide content and antioxidant compounds needs to be deeply studied. RESULTS: When looking through irrigation, regulated deficit irrigation (RDI) presented lower acrylamide levels than rainfed conditions for 'Cordovil de Elvas', 'Picual' and 'Verdeal Alentejana'. No significant interactions were found between the type of irrigation and elaboration style for 'Arbequina' and 'Koroneiki' varieties. Although RDI had the largest concentration of total phenols, antioxidant activity was also the highest. The table olives harvested in the crop year of 2019 showed lower levels of acrylamide due to a significant relationship between the crop year and irrigation conditions. CONCLUSIONS: Novel varieties to be marketed should be taken into consideration for table olive elaboration. The impact of the crop year on the bioactive value of table olives and crossover interactions relies strongly in climatological conditions. Last but not least, the benefit of selecting the best irrigation and elaboration methods is crucial to ensure desirable acrylamide levels. © 2023 Society of Chemical Industry.

Chlorophyll Pigments of Olive Leaves and Green Tea Extracts Differentially Affect Their Antioxidant and Anticancer Properties.

Plant-based extracts possess biological potential due to their high content of phytochemicals. Nevertheless, photosynthetic pigments (e.g., chlorophylls) that are also present in plant extracts could produce undesirable pro-oxidant activity that might cause a negative impact on their eventual application. Herein, the phenolic content of olive leaf (OLE) and green tea (GTE) extracts was assayed, and their antioxidant and anticancer activities were evaluated before and after the removal of chlorophylls. Regarding phenolic content, OLE was rich in hydroxytyrosol, tyrosol as well as oleuropein, whereas the main compounds present in GTE were gallocatechin, epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin gallate, and caffeine. Interestingly, fresh extracts' antioxidant ability was dependent on phenolic compounds; however, the elimination of chlorophyll compounds did not modify the antioxidant activity of extracts. In addition, both OLE and GTE had high cytotoxicity against HL-60 leukemic cell line. Of note, the removal of chlorophyll pigments remarkably reduced the cytotoxic effect in both cases. Therefore, our findings emphasize the remarkable antioxidant and anticancer potential of OLE and GTE and suggest that chlorophylls are of paramount importance for the tumor-killing ability of such plant-derived extracts.

Optimization of the Extraction of Chitosan and Fish Gelatin from Fishery Waste and Their Antimicrobial Potential as Active Biopolymers.

Fishery residues are abundant raw materials that also provide numerous metabolites with high added value. Their classic valorization includes energy recovery, composting, animal feed, and direct deposits in landfills or oceans along with the environmental impacts that this entails. However, through extraction processes, they can be transformed into new compounds with high added value, offering a more sustainable solution. The aim of this study was to optimize the extraction process of chitosan and fish gelatin from fishery waste and their revalorization as active biopolymers. We successfully optimized the chitosan extraction process, achieving a yield of 20.45% and a deacetylation degree of 69.25%. For the fish gelatin extraction process, yields of 11.82% for the skin and 2.31% for the bone residues were achieved. In addition, it was demonstrated that simple purification steps using activated carbon improve the gelatin's quality significantly. Finally, biopolymers based on fish gelatin and chitosan showed excellent bactericidal capabilities against Escherichia coli and Listeria innocua. For this reason, these active biopolymers can stop or decrease bacterial growth in their potential food packaging applications. In view of the low technological transfer and the lack of information about the revalorization of fishery waste, this work offers extraction conditions with good yields that can be easily implemented in the existing industrial fabric, reducing costs and supporting the economic development of the fish processing sector and the creation of value from its waste.

Effect of a rice bran extract-based active packaging, high pressure processing and storage temperature on the volatile compounds of sliced dry-cured high quality (Montanera) Iberian ham.

The purpose of this study was to evaluate for the first time the effect of a rice bran extract based-active packaging with antioxidant and antimicrobial activity, high pressure processing (HPP) (600 MPa, 7 min), storage time (1, 90, and 180 days) and temperature (4 vs 20 °C) on the volatile compounds of sliced "Montanera" Iberian ham. The active packaging affected a quarter of the compounds, with a trend similar (although to a greater extent) to the one resulting from the HPP. The active packaging provided no clear advantages or serious drawbacks. The slight effect of the high pressure processing indicates that "Montanera" products might be more resistant to HPP-induced changes than other dry-cured hams. Regarding storage, despite the marked effect of time (30 out of 38 compounds), the temperature only influenced two compounds. This weak effect raises the possibility of storing and distributing this vacuum-packaged sliced product at room temperature.

Antioxidant and antimicrobial evaluation of rice bran (Oryza sativa L.) extracts in a mayonnaise-type emulsion.

The objective of this study was to evaluate the in vitro antimicrobial and antioxidant activities of different bran extracts and concentrations, and their influence on the parameters of a mayonnaise-type emulsion. To that end, first ethanol and then water were used to extract two rice bran extracts (RBE) from rice bran. Both these extracts were then added at two different concentrations (0.5 and 2%) to the emulsions that were subsequently analysed after seven days under two different storage temperatures, 4 °C and 20 °C. The antioxidant and antimicrobial ability of the extracts were evaluated, along with a control and a synthetic antioxidant. Results indicate the positive effect of rice bran extracts as additives in the food matrix. Ethanolic rice bran extract (EE) at 2% decreased the oxidation as well as mould and yeast proliferation and preserved the emulsion structure, while the other treatments acted in a similar way although their effect was less pronounced.

Bioavailability, composition and functional characterization of extracts from Oryza sativa L. bran.

The aim of this study has been to assess the composition and antioxidant activities of rice bran extracts submitted to a human simulated digestion, which extraction process was previously optimized. In order to adjust the optimum values for the extraction, D-optimal experimental design and response surface methodology have been applied. Phenolic compounds and γ-oryzanol contents have been used as response parameters. In this way, two different extracts have been obtained. The first one, was obtained with 100% water as solvent, and it was mainly composed by phenolic acids. Ferulic acid was the majority compound found with a concentration of 1.00 ±â€¯0.03 mg/g extract, followed by p-coumaric acid (0.19 ±â€¯0.02 mg/g), The second extract, extracted with ethanol as solvent, was a γ-oryzanol enriched fraction with a content of 14.41 ±â€¯0.26 mg/g extract. The optimized rice bran extracts thus obtained were subjected to a process of human in-vitro digestion. In the first extract, with high polyphenol content, the phenolic content was oscillating during the digestion, like antioxidant activity. The oryzanol content found in this fraction (0.079 ±â€¯0.002 mg/g) has not been detected in any phase of digestion. In the second extract, with a high oryzanol content at the beginning, oryzanol content was not detected in any of digestion steps. However, phenolic composition was stable in all phases of simulation (ranging from 0.117 and 0.094 mg/g in the case of ferulic acid). This fact evidence that oryzanol is not a bioavailability fraction, while phenolic compounds support to some extent, the conditions of digestion.

Virgin Olive Oil Enriched with Lutein-Zeaxanthin from Spinacia oleracea.

The aim of this work consists of developing a technological process for elaborating a virgin olive oil enriched in lutein-zeaxanthin extracted from spinach, studying different parameters like temperature, time of extraction and different ratios (spinach-oil). It was observed that the amount of carotenoids extracted increased up to a maximum after 24 hours and decreased as the maceration time progressed up to 60 hours, resulting of biological degradation. It was also observed that as more spinach we added, as more lutein-zeaxanthin in the enriched virgin olive oil was obtained. The best results were obtained after 24 hours by using a 75:25 ratio at 30°C. Values of oxidative stability decreased drastically, as well as other parameters such as acidity; peroxides index and Ks were modified when the enriched virgin olive oil was subjected to 45°C for 24 hours of maceration. Thus, the present procedure constitutes a way to achieve an increase in the daily intake of beneficial compounds.