Development of functional edible oils enriched with pistachio and walnut phenolic extracts

Hydrogel microspheres immobilized lipase inspired by golf ball surfaces for the deacidification of Antarctic krill oil

Lipase-catalyzed esterification for enhancing oil quality has garnered extensive attention due to its eco-friendly and efficient merits. Nevertheless, during the catalytic esterification process at the oil-water interface to reduce acid value, the immobilized lipase is prone to detachment as a result of continuous mechanical agitation. In this study, inspired by the aerodynamic theory of golf ball surfaces, a novel immobilized enzyme system is designed and fabricated to improve the quality of Antarctic krill oil and prolong its storage time. The surface of the poly-pullulan hydrogel microspheres is chemically modified to expose numerous active reaction sites, forming a pitted structure similar to that of a golf ball. These pits on the surface of the microspheres can effectively mitigate the impact of the oil phase fluid on the immobilized enzyme on the surface of the carriers during the catalytic process, reducing lipase shedding and enhancing the catalytic reuse rate of the immobilized enzyme system. The obtained immobilized enzyme microspheres can still retain 70.1 % of the initial activity after 10 reuses. The high acid value of Antarctic krill oil (10.14mgKOH/g) can be effectively esterified and deacidified, and the acid value can be decreased to 2.18mgKOH/g.

Walnut oil prevents hyperlipidemia induced by high-fat diet and regulates intestinal flora and liver metabolism

Objective

This study aims to investigate the preventive effect of walnut oil as medicinal food on abnormal lipid metabolism and its influence on liver metabolites and intestinal flora.

Methods

The rat model of abnormal lipid metabolism was established by feeding high-fat diet and administering a high-fat emulsion via gavage. The rats were randomly assigned to one of the five groups: the normal group (ND), the model group (HFD), and three walnut oil intervention groups differing in dosage [low-dose (OL, 2.5 g/kg. BW/day), medium-dose (OM, 5 g/kg. BW/day) and high-dose (OH, 10 g/kg. BW/day)]. Modeling and administration were performed simultaneously for 10 weeks. After the last administration, the serum and organs of the animals were collected under anesthesia, and the organ index was analyzed. Serum total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) were measured. A histopathological examination of the liver was performed, and the intestinal flora was detected by Illumina technology.

Results

Compared to the ND group, the HFD group exhibited a significant increase in body weight and Lee's index. Compared to the HFD group, each walnut oil intervention group showed a relatively reduced degree of liver swelling and a significant decrease in fat vacuoles within the cytoplasm. Levels of TC, TG, LDL-C, activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly decreased (p < 0.05), while HDL-C levels were increased (p < 0.05), along with a significant increase in the activity of glutathione peroxidase (GSH-PX) and a decrease in malondialdehyde (MDA) content in serum. These findings indicated that walnut oil could improve the blood lipid profile in hyperlipidemia-model rats. The results of intestinal flora showed that at the genus level, there were significant increases in the relative abundance of Collinsella and Blautia (p < 0.01) while significant decreases of Oscillospira and Allobaculum (p < 0.01) in the HFD group vs. the ND group. However, these flora changes were impeded although only Collinslla (p < 0.05) in the OL group. Metabonomics analysis identified that a total of 19 potential biomarkers were screened out from the differential metabolites with |log2FC| > 1, VIP > 1 and p < 0.05.

Conclusion

Walnut oil can significantly prevent hyperlipidemia caused by high-fat diet. The mechanism is mainly through significantly reducing the content of MDA and the activities of ALT and AST, significantly increasing the activity of GSH-PX, and improving intestinal flora and liver metabolism.

Improving the functionality of virgin and cold-pressed edible vegetable oils: Oxidative stability, sensory acceptability and safety challenges

In recent years, there has been a growing demand for minimally processed foods that offer health benefits and premium sensory characteristics. This trend has led to increased consumption of virgin (VOs) and cold-pressed (CPOs) oils, which are rich sources of bioactive substances. To meet consumer needs for new oil products conferring multi-functional properties over a longer storage period, the scientific community has been revisiting traditional enrichment practices while exploring novel fortification technologies. In the last four years, the interest has been growing faster; an ascending number of annually published studies are about the addition of different plant materials, agri-food by-products, or wastes (intact or extracts) to VOs and CPOs using traditional or innovative fortification processes. Considering this trend, the present review aims to provide an overview and summarize the key findings from relevant papers that were retrieved from extensively searched databases. Our meta-analysis focuses on exposing the most recent trends regarding the exploitation of VOs and CPOs as substrates, the fortification agents and their form of use, as well as the fortification technologies employed. The review critically discusses possible health claim and labeling issues and highlights some chemical and microbial safety concerns along with authenticity issues and gaps in quality specifications that manufacturers have yet to address. All these aspects are examined from the perspective of developing new oil products with well-balanced techno-, senso- and bio-functional characteristics.

A Novel Strategy for the Separation of Functional Oils from Chamomile Seeds

The main aim of this study was to evaluate the oils from chamomile seeds as a new source of bioactive compounds suitable for human consumption. A green extraction technique with supercritical carbon dioxide (sc-CO2) at pressures up to 450 bar and temperatures up to 60 °C was employed for the production of a high amount of biologically active oil. Additionally, exhausted waste material was re-extracted using sc-CO2 with the addition of ethanol. By optimization in operating pressure, temperature, production cost, fraction of milled seeds, and co-solvent addition, the amount of separated chamomile oil increased from 2.4 to 18.6% and the content of unsaturated fatty acids up to 88.7%. Oils contained α-bisabolol oxide A and B in amounts up to 1.4%. Linoleic acid was detected in an amount up to 711.1 mg/g and α-linolenic acid up to 27.5 mg/g. The total phenolic content in separated oil reached 80.4 mg GAE/g while the total flavonoid content reached 11.6 mg QE/g. The obtained chamomile oils showed antioxidant activity with an IC50 of up to 3.9 mg/mL. Among the 23 tested microorganisms, the antimicrobial activity of oils was the most pronounced against Gram-positive bacteria. The cytotoxic activity of oils was tested on normal and cancer-derived cell lines. Results indicated a significant potential for oil from chamomile seeds, produced in an eco-friendly manner, as a functional food.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11947-023-03038-9.

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.

Nuts as functional foods: Variation of nutritional and phytochemical profiles and their in vitro bioactive properties

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Nutritional, biological and in vitro anti-diabetic, -obesity, -cholinergic of nuts.

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Polymeric procyanidins dominant polyphenols.

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Oleanic and pomolic acids dominant triterpenes.

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Nuts are low in Cu, Zn, Mn, Na, but rich in K and Mg.

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All nuts showed high activity in inhibiting intestinal α-glucosidase.

The aim of the present study was to examine the nutritional (fat, fatty acids, minerals, sugars) and bioactive compounds (polyphenols, tocochromanols, triterpene) and their influence on in vitro anti-diabetic (pancreatic α-amylase and intestinal α-glucosidase), anti-obesity (pancreatic lipase) and anti-cholinergic (AChE and BuChE) inhibitory activity of 8 different popular nuts—pecan, pine, hazelnuts, pistachio, almonds, cashew, walnuts, and macadamia.

The total content of phenolic compounds in nuts ranged from 432.9 (walnuts) to 5.9 (pistachio) mg/100 g. The dominant polyphenols are polymeric procyanidins (walnuts – 415.1 mg/100 g). Nuts are rich in tocochromanols (832.9–4377.5 μg/100 g), especially α- and γ-tocopherols. The highest content of α-tocopherol (vitamin E) was detected in hazelnuts and almonds (2551.0 and 2489.7 μg/100 g, respectively) while the lowest amounts were detected in macadamia, cashew and walnuts. The most abundant in nuts are oleanic and pomolic acids (35 and 22 % of total, respectively), while betulin, uvaol and erythrodiol are less characteristic triterpenes for nuts (<1%). Pine nuts are the nuts with the highest content of triterpene (690.3 mg/100 g). Pistachio and almonds are the richest in total fat (>45 %), but monounsaturated (17.5–79.3 %; hazelnuts, almonds, cashew, macadamia, pistachio and pecan) and polyunsaturated (7.5–69.3 %; pine, walnuts) are the dominant fatty acids. Moreover, nuts are low in Cu, Zn, Mn and Na content, but rich in K (464.5–1772.3 mg/100 g) and Mg (197.0–502.5 mg/100 g). Macadamia, walnuts and cashew are good sources of Se. Pistachio, almonds and cashew were characterized by the highest content of sugars, but the dominant sugar was saccharose (58.2–2399.3 mg/100 g). All nuts showed high activity in inhibiting intestinal α-glucosidase (>90 %), but lower ability to inhibit pancreatic α-amylase and pancreatic lipase activity. The activity in inhibiting acetyl- and butylcholinesterase was up to 30 %.

As described above, all nuts contain various compounds that improve the nutritional value. Therefore they should be one of the important components of the daily human diet rich in functional foods.

Why Should Pistachio Be a Regular Food in Our Diet?

The pistachio is regarded as a relevant source of biologically active components that, compared to other nuts, possess a healthier nutritional profile with low-fat content composed mainly of monounsaturated fatty acids, a high source of vegetable protein and dietary fibre, remarkable content of minerals, especially potassium, and an excellent source of vitamins, such as vitamins C and E. A rich composition in terms of phytochemicals, such as tocopherols, carotenoids, and, importantly, phenolic compounds, makes pistachio a powerful food to explore its involvement in the prevention of prevalent pathologies. Although pistachio has been less explored than other nuts (walnut, almonds, hazelnut, etc.), many studies provide evidence of its beneficial effects on CVD risk factors beyond the lipid-lowering effect. The present review gathers recent data regarding the most beneficial effects of pistachio on lipid and glucose homeostasis, endothelial function, oxidative stress, and inflammation that essentially convey a protective/preventive effect on the onset of pathological conditions, such as obesity, type 2 diabetes, CVD, and cancer. Likewise, the influence of pistachio consumption on gut microbiota is reviewed with promising results. However, population nut consumption does not meet current intake recommendations due to the extended belief that they are fattening products, their high cost, or teething problems, among the most critical barriers, which would be solved with more research and information.

Evaluating the anti-arthritic potential of walnut (Juglans regia L.) in FCA induced Sprague Dawley rats

Rheumatoid arthritis (RA) is an autoimmune progressive disease, associated with many pathophysiological consequences. Owing to the adverse effects and higher costs of pharmaceuticals, people are now looking for complementary and alternative remedies. In this milieu, the present study was designed to explore the therapeutic potential of walnuts against FCA-induced arthritis in rat models. Purposely, 50 Sprague Dawley rats were housed in a well-ventilated animal room and separated into 5 groups of 10 rats each. The rats were categorized as G₀ (negative control), G₁ (positive control, i.e., FCA induced untreated arthritic rats), G₂ (arthritic rats treated with MTX), G₃ (arthritic rats treated with walnut feed), and G₄ (arthritic rats treated with walnut extract), with an efficacy trial lasting for 42 days. The physical analysis explicated that paw swelling was significantly improved by 10%-12.8% in treatment groups after the intervention when compared with positive control. Moreover, biochemical analyses revealed significantly lower levels of ESR, CRP, and RF in rats treated with walnut-based interventions when compared to positive control. ESR values were decreased by 62.4% and 69.92% in G₃ and G₄ , whereas CRP levels were improved by 56.20% and 77.78% in G₃ and G₄ when compared with G₁ . Likewise, RF values decreased in G₂ , G₃ , and G₄ by 64.71%, 55.88%, and 69.24%, respectively when compared to G₁ . The histological examination demonstrated the potential role of walnut-based interventions in reducing the severity of disease by decreasing cell infiltration, bone erosion, and paw inflammation. Meanwhile, the gene expression analysis revealed that walnut-based interventions protected the paw joints from damage by downregulating the RANKL-OPG pathway. Conclusively, walnut feed and extract may serve as potent anti-arthritic interventions with no side effects. PRACTICAL APPLICATIONS: Plant-based therapeutics are effective in the prevention and management of various chronic diseases. The current research explored the anti-arthritic potential of walnuts. Walnut feed and extract effectively reduced the serum arthritic biomarkers as well as downregulated the genes involved in bone destruction. Thus, the inclusion of dietary ingredients having therapeutic potential such as walnuts may be synchronized in clinical practices to ameliorate arthritis.

Food-Derived Bioactive Molecules from Mediterranean Diet: Nanotechnological Approaches and Waste Valorization as Strategies to Improve Human Wellness

The beneficial effects of the Mediterranean diet (MedDiet), the most widely followed healthy diet in the world, are principally due to the presence in the foods of secondary metabolites, mainly polyphenols, whose healthy characteristics are widely recognized. However, one of the biggest problems associated with the consumption of polyphenols as nutraceutical adjuvant concerns their bioavailability. During the last decades, different nanotechnological approaches have been developed to enhance polyphenol bioavailability, avoiding the metabolic modifications that lead to low absorption, and improving their retention time inside the organisms. This review focuses on the most recent findings regarding the encapsulation and delivery of the bioactive molecules present in the foods daily consumed in the MedDiet such as olive oil, wine, nuts, spice, and herbs. In addition, the possibility of recovering the polyphenols from food waste was also explored, taking into account the increased market demand of functional foods and the necessity to obtain valuable biomolecules at low cost and in high quantity. This circular economy strategy, therefore, represents an excellent approach to respond to both the growing demand of consumers for the maintenance of human wellness and the economic and ecological exigencies of our society.

Emulsion and Microemulsion Systems to Improve Functional Edible Oils Enriched with Walnut and Pistachio Phenolic Extracts

The purpose of this research was to improve the properties of functional edible oils with potential health promoting effects, enriched with phenolic-rich extracts obtained from pistachio and walnut (5.1 and 27.4% phenolic contents respectively), by means of emulsion and micro emulsion systems. Stable water-in-oil (W/O) emulsions were obtained employing polyglycerol polyrhizinoleate (PGPR) as emulsifier (0.5, 2% H₂O in oil), despite having a whitish and opaque appearance; transparent and stable microemulsions were prepared using proper proportion (e.g., 97:3) between the oily phase and the mixture of aqueous phase and emulsifiers (3:2 lecithin-distilled monoglycerides (DMG). Total polar phenolics contents ranging between 257 and 835 mg/kg were obtained in the novel functional edible oils' formulations, reaching higher content using walnut as compared to pistachio extracts. Antioxidant capacity determined by the 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH) method increased approx. 7.5 and 1.5 times using walnut and pistachio extracts respectively. An emulsion using gallic acid and a microemulsion employing hydroxytyrosol, two well-known antioxidants, were also studied to compare antioxidant capacity of the proposed enriched oils. Furthermore, the oxidative stability of these products-very relevant to establish their commercial value-was measured under accelerated testing conditions employing the Rancimat equipment (100 °C) and performing an oven test (at 40 °C for walnut oils and 60 °C for pistachio and refined olive oils). Rancimat oxidative stability greatly increased and better results were obtained with walnut (2-3 times higher) as compared to pistachio extract enriched oils (1.5-2 times higher). On the contrary, under the oven test conditions, both the initial oxidation rate constant and the time required to reach a value of peroxide value equal to 15 (upper commercial category limit), indicated that under these assay conditions the protection against oxidation is higher using pistachio extract (2-4 times higher) than walnut's (1.5-2 times higher). Stable emulsions and transparent microemulsions phenolic-rich nut oils (250-800 mg/kg) were therefore developed, possessing a higher oxidative stability (1.5-4 times) and DPPH antioxidant capacity (1.5-7.5 times).

Oxidative stability of soybean and corn oils enriched with Pluchea quitoc hydroalcoholic extract

Soybean and corn oils are among the most popular vegetable oils, and are ingredients which are widely used in cooking and in the food industry. These oils contain many unsaturated fatty acids such as oleic, linoleic and linolenic acids, which makes them easily oxidized by oxygen. Extensive efforts are being made to prevent or minimize vegetable oil oxidation through the development of antioxidants. Phenolic antioxidants which are present in some extracts can be used as food additives to prevent lipid oxidation. In this study chromatographic analyses (HPLC and GC) of the Pluchea quitoc hydroalcoholic extract were performed. The content of phenolic compounds by the Folin-Ciocalteau method and the antioxidant properties against radicals 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) were also evaluated. The effect of samples prepared with soybean and corn oils enriched with Pluchea quitoc hydroalcoholic extract was determined and compared with samples of these oils which were free of antioxidants and with samples containing the synthetic antioxidant BHT. The results showed potential for application of the extract. A high content of phenolic compounds (314 milligrams of gallic acid equivalents (GAE)/g of extract) and good IC50 values were detected for the inhibition of the radicals DPPH and ABTS (13.2 µg·mL-1 and 5.6 µg·mL-1). In the evaluation of the oxidative stability of the oils enriched with this extract, it was found that at 1% concentration it was possible to obtain values of induction period (IP) close to the samples with added BHT.

Impact of Hydro-Alcoholic Solvents on the Oil and Phenolics Extraction from Walnut (Juglans regia L.) Press-Cake and the Self-Emulsification of Extracts

The objective was to evaluate the performance of four hydro-alcoholic solvents to simultaneously extract oil and more polar molecules as phenolics, among others, to produce complex extracts that eventually could self-emulsify after solvent removal. Walnut press-cake was selected as the sourcing material. Extractions were performed as a semi-continuous operation up to a solvent-to-solid ratio of 28, with a fractional collection of the effluent. Among the solvents, labelled by their alcohol content EtOH 58, EtOH 86, iPro 60 and iPro 90 for ethanol (EtOH) and isopropanol (iPro), iPro 90 allowed to reach an oil extraction efficiency of 97% while the recovery for the other solvents was in the range of 30–40%. For both alcohols, the increase of the solvent hydration negatively influenced the oil extraction but positively increased the recovery of phenolics that reached 17.6 mg GAE/g_cake when EtOH 58 was used. Several fractions contained enough surface-active material and oil to self-assemble as emulsions. IPro 90 and EtOH 86 showed better performances in the sense that most extracts were able to emulsify, though extraction kinetics pointed out differences. The most hydrated solvents behaved equally, with extraction yields in the same range and a similar but limited emulsifying capacity of only few fractions.

Determination of Metals in Walnut Oils by Means of an Optimized and Validated ICP-AES Method in Conventional and Organic Farming Type Samples

Agricultural products are indispensable for equilibrated diets since they discharge minerals and several bioactive constituents. Considering the increasing demand for organic products, research has been conducted over recent years to investigate whether organically grown food products are chemically different compared to those produced with conventional farming. In this work, a novel inductively coupled plasma atomic emission spectrometric method was developed and validated for the determination of nutrient and toxic elements in walnut oils produced with conventional and organic farming. The method presented good linearity (r2 > 0.9990) for each element at the selected emission line. The limits of detection and limits of quantification ranged between 0.09 μg g−1 to 2.43 μg g−1 and 0.28 μg g−1 to 8.1 μg g−1, respectively. Method accuracy and was assessed by analyzing the certified reference materials BCR 278-R and spiked walnut oil samples. The determined metals were quantified, and the results were analyzed by Student’s t-test to investigate the differences in the elemental profile of the walnut oils according to type of farming (conventional or organic).

Exploration of walnut components and their association with health effects

Traditionally, walnuts have occupied an imperative position in the functional food market with consistently recognized nutritious and functional properties. In the past years, the lipid profile of walnuts has brought much scientific attention via linking a cascade of biological attributes and health-promoting effects. Over time, researchers have focused on diversified composition (polyphenols and vitamins) of different parts of walnut (flower, pellicle, and kernel) and emphasized their physiological significance. Consequently, a plethora of reports has emerged on the potential role of walnut consumption against a series of diseases including cancer, gut dysbiosis, cardiovascular, and neurodegenerative diseases. Therefore, we accumulated the updated data on composition and classification, extraction methods, and utilization of different parts of walnuts as well as associated beneficial effects under in vivo and clinical studies. Altogether, this review summarized the ameliorative effects of a walnut-enriched diet in chronic diseases which can be designated to the synergistic or individual effects of walnut components mainly through anti-oxidative and anti-inflammatory role.