Structuring vegetable oils through enzymatic glycerolysis for water-in-oil emulsions.

Enzymatic glycerolysis is a biotechnological process for structuring vegetable oils. This study investigates the kinetics of glycerolysis of peanut oil and explores the potential of the resulting structured oil to enhance the physical stability of water-in-oil emulsions. Using a 1:1 glycerol-to-oil molar ratio and 4 % lipase B from Candida antarctica as a catalyst, the reaction was conducted at 65 °C with stirring at 400 rpm. Acylglyceride fractions changes were quantified through NMR and DSC. Fat crystal formation was observed using scanning electron microscopy. The results revealed a first-order decay pattern, converting triglycerides into monoacylglycerides and diacylglycerides in less than 16 h. Subsequently, water-in-oil emulsions prepared with glycerolized oil showed augmented stability through multiple light scattering techniques and visual assessment. The structured oils effectively delayed phase separation, highlighting the potential of glycerolysis in developing vegetable oil-based emulsions with improved functional properties and reduced saturated fatty acid content.

Early detection of acrolein precursors in vegetable oils by using proton transfer reaction - mass spectrometry.

Acrolein is a toxic volatile compound derived from oxidative processes, that can be formed in foods during storage and cooking. This study employs proton transfer reaction mass spectrometry (PTR-MS) to detect acrolein precursors in vegetable oils by focusing on the m/z (mass-to-charge ratio) 57. To this purpose, hempseed, sesame, walnut, olive and linseed oils were stored for 168 h at 60 °C in presence of 2,2'-azobis(2-metilpropionitrile) (3 mM) radicals initiator. The evolution of m/z 57 by PTR-MS was also compared with traditional lipid oxidation indicators such as peroxide value, conjugated diene, oxygen consumption and, isothermal calorimetry. The obtained results were explained by the fatty acid composition and antioxidant capacity of the oils. Hempseed fresh oil presented a very low total volatile organic compounds (VOCs) intensity (5.6 kncps). Nonetheless, after storage the intensity increased ∼70 times. A principal component analysis (PCA) confirmed the potential of m/z 57 to differentiate fresh versus rancid hempseed oil sample. During an autoxidation experiment oils high in linolenic and linoleic acids showed higher m/z 57 emissions and shorter induction times: linseed oil (38 h) > walnut oil (47 h) > hempseed oil (80 h). The m/z 57 emission presented a high correlation coefficient with the total VOC signal (r > 0.95), conjugated dienes and headspace oxygen consumption. A PCA analysis showed a complete separation of the fresh oils on the first component (most significant) with the exception of olive oil. Walnut, hempseed and linseed oil were placed on the extreme right nearby total VOCs and m/z 57. The results obtained highlight the potential of PTR-MS for the early detection of oil autoxidation, serving as a quality control tool for potential acrolein precursor emissions, thereby enhancing food safety in the industry.

In Vivo Anti-Inflammatory Effect, Antioxidant Activity, and Polyphenolic Content of Extracts from Capsicum chinense By-Products.

By-products of Capsicum chinense Jacq., var Jaguar could be a source of bioactive compounds. Therefore, we evaluated the anti-inflammatory effect, antioxidant activity, and their relationship with the polyphenol content of extracts of habanero pepper by-products obtained from plants grown on black or red soils of Yucatán, Mexico. Moreover, the impact of the type of extraction on their activities was evaluated. The dry by-product extracts were obtained by maceration (ME), Soxhlet (SOX), and supercritical fluid extraction (SFE). Afterward, the in vivo anti-inflammatory effect (TPA-induced ear inflammation) and the in vitro antioxidant activity (ABTS) were evaluated. Finally, the polyphenolic content was quantified by Ultra-Performance Liquid Chromatography (UPLC), and its correlation with both bioactivities was analyzed. The results showed that the SFE extract of stems of plants grown on red soil yielded the highest anti-inflammatory effect (66.1 ± 3.1%), while the extracts obtained by ME and SOX had the highest antioxidant activity (2.80 ± 0.0052 mM Trolox equivalent) and polyphenol content (3280 ± 15.59 mg·100 g-1 dry basis), respectively. A negative correlation between the anti-inflammatory effect, the antioxidant activity, and the polyphenolic content was found. Overall, the present study proposed C. chinense by-products as a valuable source of compounds with anti-inflammatory effect and antioxidant activity.

Inhibition of lipid autoxidation by vegetable waxes.

This study aims to evaluate the effect of vegetable waxes on the kinetics of lipid oxidation of linseed oil. Apple and orange waxes were obtained using supercritical carbon dioxide. The capacity of waxes to inhibit or retard the oxidation of linseed oil was determined by isothermal calorimetry at 298 K. The results show that waxes were able to slow down linseed oil autoxidation, with apple waxes being more active than orange waxes. However, such activity was visible only at relatively high concentrations (>1% of waxes), greatly higher than the concentration used with radical chain breakers like BHT (0.2%). The inhibition activity was explained by considering three different mechanisms: (1) residual polyphenol content in the wax, (2) high termination rate of the radical chain process, and (3) physical hindrance of the oxidation process by change in viscosity. All these mechanisms were possible, although the latter seemed to be the most important. Finally, the importance of waxes in the inhibition of lipid autoxidation was determined by testing their inhibition activity in combination with primary antioxidants. A mixture of waxes with BHA, ethoxyquin and α-tocopherol showed a higher rate of inhibition than when present individually. This suggested a strong cooperative radical scavenging activity, whose beneficial effect might pave the way to the formulation of novel functional ingredients.

Extraction of Essential Oils from Medicinal Plants and their Utilization as Food Antioxidants.

BACKGROUND: The use of essential oils is receiving increasing attention worldwide, as these oils are good sources of several bioactive compounds. Nowadays essential oils are preferred over synthetic preservatives thanks to their antioxidant and antimicrobial properties. Several studies highlight the beneficial effect of essential oils extracted from medicinal plants to cure human diseases such as hypertension, diabetes, or obesity. However, to preserve their bioactivity, the use of appropriate extraction technologies is required. METHODS: The present review aims to describe the studies published so far on the essential oils focusing on their sources and chemical composition, the technologies used for their recovery and their application as antioxidants in food products. RESULTS: The review has been structured in three parts. In the first part, the main compounds present in essential oils extracted from medicinal plants have been listed and described. In the second part, the most important technologies used for extraction and distillation, have been presented. In detail, conventional methods have been described and compared with innovative and green technologies. Finally, in the last part, the studies related to the application of essential oils as antioxidants in food products have been reviewed and the main findings discussed in detail. CONCLUSION: In summary, an overview of the aforementioned subjects is presented by discussing the results of the most recent published studies.

Antimicrobial Effect of Picea abies Extracts on E. coli Growth.

This study aims to investigate the effect of essential oils extracted from wood residues of Picea abies on the growth of Escherichia coli. The essential oils were extracted by supercritical carbon dioxide, leading to a yield of 3.4 ± 0.5% (w/w) in 120 min. The antimicrobial effect was tested at 37 °C by isothermal calorimetry. The heat-flow (dq/dt vs. time) was integrated to give a fractional reaction curve (α vs. time). Such curves were fitted by a modified Gompertz function to give the lag-time (λ) and the maximum growth rate (µmax) parameters. The results showed that λ was linearly correlated with E. coli concentration (λ = 1.4 h/log (CFU/mL), R2 = 0.997), whereas µmax was invariant. Moreover, the overall heat was nearly constant to all the dilutions of E. coli. Instead, when the essential oil was added (with concentrations ranging from 1 to 5 mg/L) to a culture of E. coli (104 CFU/mL), the lag-time increased from 14.1 to 33.7 h, and the overall heat decreased from 2120 to 2.37 J. The results obtained by the plate count technique were linear with the lag-time (λ), where (λ = -7.3 × log (CFU/mL) + 38.3, R2 = 0.9878). This suggested a lower capacity of E. coli to metabolize the substrate in the presence of the essential oils. The results obtained in this study promote the use of essential oils from wood residues and their use as antimicrobial products.

Current technologies and new insights for the recovery of high valuable compounds from fruits by-products.

The recovery of high valuable compounds from food waste is becoming a tighten issue in food processing. The large amount of non-edible residues produced by food industries causes pollution, difficulties in the management, and economic loss. The waste produced during the transformation of fruits includes a huge amount of materials such as peels, seeds, and bagasse, whose disposal usually represents a problem. Research over the past 20 years revealed that many food wastes could serve as a source of potentially valuable bioactive compounds, such as antioxidants and vitamins with increasing scientific interest thanks to their beneficial effects on human health. The challenge for the recovery of these compounds is to find the most appropriate and environment friendly extraction technique able to achieve the maximum extraction yield without compromising the stability of the extracted products. Based on this scenario, the aim of the current review is twofold. The first is to give a brief overview of the most important bioactive compounds occurring in fruit wastes. The second is to describe the pro and cons of the most up-to-dated innovative and environment friendly extraction technologies that can be an alternative to the classical solvent extraction procedures for the recovery of valuable compounds from fruit processing. Furthermore, a final section will take into account published findings on the combination of some of these technologies to increase the extracts yields of bioactives.