Antioxidant Efficacy of Rosemary Extract in Improving the Oxidative Stability of Rapeseed Oil during Storage

Rapeseed oil is an important source of edible oil in the human diet and is also highly susceptible to oxidative deterioration. It has been demonstrated that rosemary extract (RE) can increase the oxidative stability of oils. In this work, the antioxidant capacity of rapeseed oil after the addition of RE during storage and the optimum addition of RE in rapeseed oil were investigated. Oxidative stability evaluation results demonstrate that the shelf life of rapeseed oil with the incorporation of 100 mg/kg of RE was equivalent to that with the addition of 50 mg/kg of tert-butyl hydroxyquinone (TBHQ). Storage test analysis results show that RE remarkably delayed the oxidation of rapeseed oil when the storage container was unsealed. The optimum amount of RE as an addition was 50-200 mg/kg under room temperature storage, while it was 150 mg/kg under Schaal oven storage. The antioxidant capacity of rapeseed oil with 50 mg/kg of RE added was remarkably higher than that with 50 mg/kg of TBHQ added after 20 d of storage, according to the Schaal oven test. Additionally, the addition of RE delayed the degradation of endogenous α-tocopherol in rapeseed oil. This study comprehensively evaluated the antioxidant properties of rapeseed oil when RE was added and it provides a new strategy for establishing healthy, nutritious, and safe oil preservation measures.

In vitro anti-ageing activities of ethanolic extracts from Pink rambutan (Nephelium lappaceum Linn.) for skin applications

Skin ageing is characterized by features such as wrinkles, loss of elasticity, laxity, rough-textured appearance, melasma and freckles. Several researches have focused for preventing, and treating skin ageing by many natural ingredients. This study aimed to assess the anti-ageing activities for anti-skin ageing of the ethanolic extracts of Pink rambutan (PR) (Nephelium lappaceum Linn.) from leaves (L), branches (B), seeds (S), and peels from ripe (R) and young (Y) fruits. The extraction yields of all Pink Rambutan (PR) extracted by the Maceration (M) and the Soxhlet extraction (Sox) using 95% ethanol as a solvent, ranged from 10.62% to 30.63%. Flavonoids were found as the main phytochemicals in almost all the PR extracts. The PR-Y-M and PR-Y-Sox extracts gave the highest total phenolic contents by the Folin-Ciocalteu assay of 67.60 ± 4.38 mgGAE/g, and total flavonoid contents by the modified aluminum chloride colorimetric assay of 678.72 ± 23.59 mgQE/g, respectively. The PR-L-M extracts showed the highest three anti-oxidative activities; the free radical scavenging (SC₅₀ of 0.320 ± 0.070 mg/mL), the lipid peroxidation inhibition (LC₅₀ of 0.274 ± 0.029 mg/mL), and the metal chelation activity (MC₅₀ of 0.203 ± 0.021 mg/mL). All the PR extracts at 0.01 and 0.1 mg/mL showed no cytotoxicity on B₁₆F₁₀ cells, and human skin fibroblasts, respectively. Likewise, the PR-R-Sox extract exhibited the highest anti-melanogenesis on B₁₆F₁₀ cells (52.7 ± 0.9%) and, the mushroom tyrosinase inhibition activity (IC₅₀ of 0.04 ± 0.02 mg/mL), which was significantly comparable to kojic acid (p < 0.05). The PR-Y-Sox extract showed the collagen biosynthesis by the Sirius Red method, and the stimulation of anti-ageing genes (Sirt1 and Foxo1) on human skin fibroblasts by the RT-PCR method, which were similar to standards ʟ-ascorbic acid and resveratrol, respectively. This study suggests that the PR-R-Sox and PR-Y-Sox extracts can be further developed as natural anti-ageing agents for whitening and anti-wrinkle in the cosmetics, cosmeceutical, and pharmaceutical industries.

Optimization of accelerated aqueous ethanol extraction to obtain a polyphenol-rich crude extract from rambutan (Nephelium lappaceum L.) peel as natural antioxidant

An accelerated solvent extraction method was used to recover polyphenol-rich crude extract from rambutan (Nephelium lappaceum L.) peel, a waste product from the canning industry. The influence of extraction parameters including temperature, extraction time and ethanol concentration on extraction yield, total phenolic content, total anthocyanin content, and ABTS antioxidant activity was investigated. A Box-Behnken design and response surface methodology were used to optimize the extraction process. Optimal conditions were obtained at temperature, extraction time, and ethanol concentration of 60 °C, 34 min, and 54 vol%, respectively. These optimum conditions gave 333.01 ± 5.84 mg gallic acid/g, 318.28 ± 5.56 mg cyanidin-3-O-glucoside/g, and 3.05 ± 0.04 mmol Trolox/mg for total phenolic content, total anthocyanins content, and ABTS activity, respectively with extraction yield of 28.68 ± 1.48 wt%. Important active compounds found in the extract were geraniin, ellagic acid, shikimic acid and corilagin. Crude extract concentrations of 50-500 mg/kg retarded linoleic acid oxidation but efficacy was lower than synthetic antioxidants at 200 mg/kg. The current findings indicated that accelerated aqueous ethanol extraction was an effective method for the recovery of a crude extract rich in polyphenols from rambutan peel with the potential to be used as a natural antioxidant.

An Overview on the Use of Extracts from Medicinal and Aromatic Plants to Improve Nutritional Value and Oxidative Stability of Vegetable Oils

Oil oxidation is the main factor limiting vegetable oils' quality during storage, as it leads to the deterioration of oil's nutritional quality and gives rise to disagreeable flavors. These changes make fat-containing foods less acceptable to consumers. To deal with this problem and to meet consumer demand for natural foods, vegetable oil fabricators and the food industry are looking for alternatives to synthetic antioxidants to protect oils from oxidation. In this context, natural antioxidant compounds extracted from different parts (leaves, roots, flowers, and seeds) of medicinal and aromatic plants (MAPs) could be used as a promising and sustainable solution to protect consumers' health. The objective of this review was to compile published literature regarding the extraction of bioactive compounds from MAPs as well as different methods of vegetable oils enrichment. In fact, this review uses a multidisciplinary approach and offers an updated overview of the technological, sustainability, chemical and safety aspects related to the protection of oils.

Effect of Natural Antioxidants from Fruit Leaves on the Oxidative Stability of Soybean Oil during Accelerated Storage

Plant by-products are safe, sustainable, and abundant natural antioxidant sources. Here we investigated the antioxidant activity of a mixture of lyophilized pomegranate, guava, and grape (PGG) leaves water extract (1:1:1) and examined its ability to retard the rancidity of soybean oil during accelerated storage at 65 °C for 30 days. To achieve this, we evaluated the oxidative stability of soybean oil enriched with PGG extract at 200, 400, and 800 ppm. We also compared the effect of PGG extract with butylated hydroxytoluene (BHT) (400/100 ppm) with that of only BHT (200 ppm). We observed that 8.19 and 1.78 µg/mL of the extract could scavenge 50% of DPPH• and ABTS•, respectively, indicating its enhanced antioxidant activity. Enriching soyabean oil with the extract at 800 ppm improved its oxidative stability by reducing the acid value to 1.71 mg/g and the total oxidation to 99.87 compared to 2.27 mg/g and 150.32 in the raw oil, respectively. Moreover, PGG-800 ppm inhibited oxidation by 46.07%. Similarly, PGG-400 ppm reinforced BHT (100 ppm) to provide oxidative stability as BHT (p > 0.05), with TOTOX values of 87.93 and 79.23, respectively. PGG-800 ppm and PGG/BHT mix potently inhibited the transformation of polyunsaturated fatty acids into saturated ones. Therefore, the PGG extract might be an efficient substitute for BHT (partially or totally) during industrial processes.

Eugenol, Isolated from the Essential Oil from Lonicera japonica Flower Buds, Could Increase the Oxidative Stability of Sunflower Oil in the Deep-Frying Procedure of Youtiao

In order to assess the sunflower oil (SFO) oxidative stability that was added by the essential oils extracted from Lonicera japonica flower buds (LJEO) during deep-frying at 180 °C for 30 h, we clarified the compound/compounds of LJEO that improved the oxidative stability of SFO. The results displayed that the addition of LJEO (0.06 g/kg) could significantly restrict the elevation or the reduction in the levels of total polar compounds (TPC), thiobarbituric acid (TBA), conjugated dienes and conjugated trienes, and the values for polymer, viscosity and the color of SFO during the whole period. Meanwhile, the reduction in the sensory attributes, including flavor, taste, crispness and overall acceptability of the fried product, youtiao, was obviously restricted as well. After the bioassay-guided fractionation of LJEO and repeated deep-frying at 180 °C for 30 h, one of its chemical constituents, eugenol, was demonstrated to be the very compound that did significantly inhibit the oxidative rancidity of the SFO. Therefore, eugenol may be employed as potential effective natural antioxidants to inhibit the oxidative rancidity of SFO during its deep-frying procedures.

Improving the Oxidation Stability and Shelf-Life of Peanut Oil by Addition of Rosemary Extract Combined with Vitamin C and Ascorbyl Palmitate

Rosemary extracts are natural antioxidants, which can be considered an alternative for synthetic antioxidants in the food industry. The aim of the present study was to evaluate the oxidation stability and shelf-life of rosemary extracts combined with vitamin C (VC) and ascorbyl palmitate (AP) in peanut oil stored at 65°C. Peanut oil with tertbutyl hydroquinone (TBHQ) and without additives served as positive and negative controls, respectively. The peroxide value (POV), thiobarbituric acid reactant (TBARs), conjugated diene (CD), and conjugated triene (CT) values of the peanut oil samples were evaluated during accelerated storage every 48 h. Among them, 0.23 g/kg rosemary extracts combined with 0.13 g/kg VC and 0.07 mg/kg AP exhibited the best oxidative stability. Additionally, the oxidation kinetics model predicated that the rosemary extracts combined with VC and AP could effectively prolong the shelf-life of peanut oil. In accelerated storage, the rosemary extracts combined with VC and AP not only inhibited peanut oil oxidation like chemical antioxidants, but also were safer than chemical antioxidants. Therefore, the rosemary extracts combined with VC and AP were an effective alternative to chemical antioxidants, which could improve the oxidation stability and shelf-life of peanut oil.

Functional and nutritional properties of selected Amazon fruits: A review

This review reports the nutritional, phytochemical compounds and biological properties of 4 fruits commonly consumed by people living in Amazon region, namely Biribá (Rollinia mucosa Jacq.), Rambutan (Nephelium lappaceum L.), Pupunha (Bactris gasipaes Kunth) and Tucumã (Astrocaryum aculeatum Meyer). These fruits have been high held nutritional, functional and economic potential and contribute to the daily intake of nutrients, energy and bioactive compounds by people living in Amazon rainforest region. Phytochemical compounds with biological properties were detected in these fruits, for instance (but not limited to), annonaceous acetogenins in Biribá, geraniin and corilagin in Rambutan, rutin and catechin in Pupunha, and β-carotene and flavonoids in Tucumã. The biological properties of Biribá, Rambutan, Pupunha and Tucumã have been evaluated by in vitro and in vivo assays, especially antioxidant and antimicrobial activities. Therefore, these Amazonian fruits can be exploited by the food industry as a food and therapeutic plant-material to develop valuable products, such as medicine products and can be used as sources for obtaining compounds for the food, cosmetics and pharmaceutical applications.

Green Tea Extract Enhances the Oxidative Stability of DHA-Rich Oil

Docosahexaenoic acid (DHA) is one of the most important omega-3 polyunsaturated fatty acids, with proven health-promoting properties. However, oils with a very high content in DHA (DHAO) are extremely susceptible to oxidation, which affects shelf stability and limits incorporation in food products. Green tea extracts (GTE) are potential candidates for the protection of these oils, but their use in such oils has not been previously reported. This study investigated the effect of GTE (160 ppm, 400 ppm, 1000 ppm) and α-tocopherol (80 ppm, 200 ppm, 500 ppm) on the oxidative stability of a DHAO over a 9-week storage at 30 °C. The oxidative status was monitored during storage by the measurement of peroxide value (PV) and p-anisidine value (p-AV). Changes in eicosapentaenoic acid (EPA) and DHA content, as well as in catechins and tocopherol contents, were also evaluated. The addition of GTE enhanced the oxidative stability of DHAO by reducing the formation of peroxides and secondary oxidation products, whereas α-tocopherol had no significant effect on the PV of oil during storage but led to a significantly higher p-AV. The EPA and DHA content of DHAO was stable in GTE-supplemented samples whereas a decrease was observed in the control and α-tocopherol-supplemented samples. GTE also delayed the degradation of tocopherols initially present in the oil, while catechins resulting from the addition of GTE decreased progressively during the storage period.

An Overview of Natural Extracts with Antioxidant Activity for the Improvement of the Oxidative Stability and Shelf Life of Edible Oils

Many plant materials, such as fruits and vegetables as well as herbs and spices, represent valuable sources of antioxidants. In recent years, wastes from agriculture and food industrial processes have been shown to be interesting sources for bioactive compound recovery, strongly contributing to the circular economy. Nowadays, because of their possible adverse effects on human health, there is a tendency to replace synthetic antioxidants with natural compounds. This review attempts to critically summarize the current evidence on plant bioactives, extracted from food or waste, added to unsaturated vegetable oils, in order to obtain high added-value products and to ameliorate their oxidative stability and shelf life. The goal of this review is to demonstrate the current status of the research on edible oils added with natural plant bioactives, highlighting new approaches in the field of health-promoting foods.