A review of the nutritional composition, organoleptic characteristics and biological effects of the high oleic peanut

Groundnut and tree nuts: a comprehensive review on their lipid components, phytochemicals, and nutraceutical properties

The health benefits of nut consumption have been extensively demonstrated in observational studies and intervention trials. Besides the high nutritional value, countless evidences show that incorporating nuts into the diet may contribute to health promotion and prevention of certain diseases. Such benefits have been mostly and certainly attributed not only to their richness in healthy lipids (plentiful in unsaturated fatty acids), but also to the presence of a vast array of phytochemicals, such as polar lipids, squalene, phytosterols, tocochromanols, and polyphenolic compounds. Thus, many nut chemical compounds apply well to the designation "nutraceuticals," a broad umbrella term used to describe any food component that, in addition to the basic nutritional value, can contribute extra health benefits. This contribution analyses the general chemical profile of groundnut and common tree nuts (almond, walnut, cashew, hazelnut, pistachio, macadamia, pecan), focusing on lipid components and phytochemicals, with a view on their bioactive properties. Relevant scientific literature linking consumption of nuts, and/or some of their components, with ameliorative and/or preventive effects on selected diseases - such as cancer, cardiovascular, metabolic, and neurodegenerative pathologies - was also reviewed. In addition, the bioactive properties were analyzed in the light of known mechanistic frameworks.

Flavor Characteristics of Ten Peanut Varieties from China

To investigate the flavor characteristics of peanuts grown in Jiangsu, China, ten local varieties were selected. The amino acids, 5'-nucleotides and volatile substances were detected, and the flavor and odor characteristics of these varieties were estimated using an electronic tongue and nose. The results showed that the fat and protein contents of ten peanut varieties changed significantly (p < 0.05), and may have been negatively correlated with those of the Taihua 6 variety-in particular, having the highest protein content and the lowest fat content. The amino acid contents of the peanuts were 20.08 g/100 g (Taihua 4)-27.18 g/100 g (Taihua 6). Taihua 6 also contained the highest bitter (10.41 g/100 g) and sweet (6.06 g/100 g) amino acids, and Taihua 10 had the highest monosodium glutamate-like amino acids (7.61 g/100 g). The content of 5'-nucleotides ranged from 0.08 mg/g (Taihua 9725) to 0.14 mg/g (Taihua 0122-601). Additionally, 5'-cytidylate monophosphate (5'-CMP) and 5'-adenosine monophosphate (5'-AMP) were the major 5'-nucleotides detected in the peanuts. A total of 42 kinds of volatile flavor compounds were detected, with both Taihua 4 and 6 showing the most (18 kinds) and the highest content being in Taihua 4 (7.46%). Both Taihua 9725 and 9922 exhibited the fewest kinds (nine kinds) of volatile components, and the lowest content was in Taihua 9725 (3.15%). Formic acid hexyl ester was the most abundant volatile substance in peanuts, and the highest level (3.63%) was detected in Taihua 7506. The electronic tongue and nose indicated that the greatest taste difference among the ten varieties of peanuts was mainly related to sourness, and Taihua 4 and Taihua 9922 had special taste characteristics. On the other hand, the greatest smell difference among the ten varieties of peanuts was mostly for methane and sulfur organic substances, and Taihua 0605-2 had a special and strong smell characteristic. In conclusion, the content and composition differences of the flavor substances of ten peanut varieties were responsible for their divergences in taste and smell. These results will provide guidelines for the further use (freshly consumed or processed) of these ten peanut varieties.

Effects of high oleic acid peanuts on mice's liver and adipose tissue metabolic parameters and gut microbiota composition

This study aimed to investigate the effects of two types of peanuts, regular Hanoch (HN) and a new high-oleic cultivar., Hanoch-Oleic (HO), on metabolic parameters and gut microbiota composition. Male C57BL/6 mice were fed with a normal diet (ND) or ND supplemented with HN (NDh) or HO (NDo). Following 18 weeks of diet regimen, the NDo group exhibited reduced body weight and peri-gonadal adipose-to-body weight ratio, paralleled to lesser food consumption. Although blood levels of total cholesterol, HDL-cholesterol, free fatty acids, and liver enzyme levels did not differ between groups, decreased insulin sensitivity was found in the NDh group. Within adipose tissue, the expression of lipolytic and lipogenic enzymes was higher, while those related to lipid oxidation were lower in the NDh group compared to the NDo group. Additionally, HO peanuts consumption promoted the establishment of a healthy microbiota, with an enhanced abundance of Bifidobacterium, Lactobacillus, and Coprococcus genera. In conclusion, the inclusion of the HO peanut cultivar., rather than the conventional peanut cultivar., in a balanced diet was related to better metabolic outcomes and was linked to a favorable microbiota profile.

Seed Weight and Genotype Influence the Total Oil Content and Fatty Acid Composition of Peanut Seeds

Peanut, an important oilseed crop cultivated worldwide as a dietary food, is a good food source with health benefits. To explore the potential benefits of peanuts as a food resource, 301 peanut accessions were evaluated to determine the effect of seed weight and genotype on total oil content and fatty acid composition. Total oil was extracted using the Soxhlet method and fatty acids were analyzed by gas chromatography mass spectrometry. Wide variations in the 100-seed weight, total oil content, and fatty acid profile were observed among genotypes and accession types. An effect of seed weight on the fatty acid composition of peanut seeds was observed. Increases in the oleic acid content and decreases in the linoleic acid content occurred in association with increases in the 100-seed weight. Moreover, the 100-seed weight, total oil content, and individual and total fatty acid contents, except arachidic acid, differed significantly (p < 0.001 or 0.05) among the accession types of landrace, cultivar, breeding line, and unknown. The discovery of this high diversity could contribute to further studies of peanut domestication and evolutionary classification. Our findings are important for the selection of peanut seeds with health benefits and development of new varieties of peanut with health benefits.

Breeding of a new variety of peanut with high-oleic-acid content and high-yield by marker-assisted backcrossing

Peanut (Arachis hypogaea L.) is an important crop used for oil production, and oleic acid is a major factor in determining oil quality. Alterations in the oleic acid content can improve the nutritional quality and oxidative stability and prolong the shelf life of peanut products. The objective of this study was to develop a peanut variety with a high-oleic-acid content and high yield. One elite variety, "huayu22," was hybridized with the high-oleic-acid "KN176" donor and backcrossed for four generations as the recurrent parent using fad2 marker-assisted backcross selection. Based on the Kompetitive allele-specific PCR (KASP) screening of fad2 markers, the oleic acid content of advanced generations derived by selfing was assessed by near-infrared reflectance spectroscopy and gas chromatography. The genetic background recovery rate of four BC4F4 lines showed an average of 92.34% and was confirmed by genotyping using the Axiom_Arachis 58 K SNP array. Across these superior lines in BC4F6 generations, one line with a high-oleic-acid content and high yield was detected and named "YH61." In particular, yield comparison experiments showed that YH61 exhibited high and stable yield at three different locations and was moderately resistant to leaf spot disease. The distinctness, uniformity and stability (DUS) testing for two consecutive years suggested that YH61 reached the standard for variety rights application. The use of the peanut variety YH61 contributed to the expansion of the cultivation area due to its high value in the oleic acid market and the proven economic benefits in China. This study demonstrated that the marker-assisted backcross strategy based on a cost-effective KASP assay and SNP array for the detection of mutations in fad2 and genetic background evaluation can be used to create efficient peanut breeding programs and contribute to oil quality and high-yield stability.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11032-022-01313-9.

Study on Key Aroma Compounds and Its Precursors of Peanut Oil Prepared with Normal- and High-Oleic Peanuts

High-oleic acid peanut oil has developed rapidly in China in recent years due to its high oxidative stability and nutritional properties. However, consumer feedback showed that the aroma of high-oleic peanut oil was not as good as the oil obtained from normal-oleic peanut variety. The aim of this study was to investigate the key volatile compounds and precursors of peanut oil prepared with normal- and high-oleic peanuts. The peanut raw materials and oil processing samples used in the present study were collected from a company in China. Sensory evaluation results indicated that normal-oleic peanut oil showed stronger characteristic flavor than high-oleic peanut oil. The compounds methylpyrazine, 2,5-dimethylpyrazine, 2-ethyl-5-methylpyrazine and benzaldehyde were considered as key volatiles which contribute to dark roast, roast peanutty and sweet aroma of peanut oil. The initial concentration of volatile precursors (arginine, tyrosine, lysine and glucose) in normal-oleic peanut was higher than in high-oleic peanut, which led to more characteristic volatiles forming during process and provided a stronger oil aroma of. The present research will provide data support for raw material screening and sensory quality improvement during high-oleic acid peanut oil industrial production.

Development of high oleic peanut lines through marker-assisted introgression of mutant ahFAD2 alleles and its fatty acid profiles under open-field and controlled conditions

Peanut is one of the most important oilseed crops grown worldwide. In this study, the mutant ahFAD2 alleles conferring high oleic (HO) content are introgressed into an elite Indian cultivar GPBD4 which is also resistant to the foliar fungal diseases like rust and late leaf spot (LLS). The allele-specific PCR (AS-PCR) and cleaved amplified polymorphic sequences (CAPS) assays were used for the marker-assisted backcross (MABC) approach and 64 HO introgression lines (ILs) were generated. These ILs were tested for the FA compositions under the glasshouse and field conditions. The oleic acid and linoleic acid contents in the ILs were recorded to be between 68.94-82.33% and 1.74-10.87%, respectively, under glasshouse and 67.04-81.71% and 2.00-15.66%, respectively, under field conditions. The increase in the oleic acid content of the ILs over its recurrent parent (RP) was recorded to the tune of 28.78-53.80% and 33.70-62.96% under glasshouse and field conditions, respectively, indicating the stable expression of ahFAD2B gene in two different environments. On the contrary, linoleic acid showed 56.47-93.03% and 40.02-92.34% reduction in the ILs over its RP under glasshouse and field conditions, respectively. These ILs with a healthy FA profile can meet not only the nutritional requirements of a health-conscious society but also the industrial demands for better shelf life of oil and its products.

Harnessing Biotechnology for the Development of New Seed Lipid Traits in Brassica

The seed oil quality of Brassica oilseed species has been improved in the last few decades, using conventional breeding approaches. Modern biotechnology has enabled the significant development of new seed lipid traits in many oil crops. Alternation of seed lipid component with gene knockout by RNAi gene silencing, artificial microRNA or gene editing within the crop is relative straightforward. Introducing a new pathway from an exogenous source via biotechnology enables the creation of a new trait, where the biosynthetic pathway for such a new trait is not available in the host crop. This review updates the recent development of new seed lipid traits in six major Brassica species and highlights the capability of biotechnology to improve the composition of important fatty acids for both industrial and nutritional purposes.

Role of dietary lipids in food allergy

The prevalence of food allergy is raising in industrialized countries, but the mechanisms behind this increased incidence are not fully understood. Environmental factors are believed to play a role in allergic diseases, including lifestyle influences, such as diet. There is a close relationship between allergens and lipids, with many allergenic proteins having the ability to bind lipids. Dietary lipids exert pro-inflammatory or anti-inflammatory functions on cells of the innate immunity and influence antigen presentation to cells of the adaptive immunity. In addition to modifying the immunostimulating properties of proteins, lipids also alter their digestibility and intestinal absorption, changing allergen bioavailability. This study provides an overview of the role of dietary lipids in food allergy, taking into account epidemiological information, as well as results of mechanistic investigations using in vivo, ex vivo and in vitro models. The emerging link among high-fat diets, obesity, and allergy is also discussed.

Sensory and Chemical Stabilities of High-Oleic and Normal-Oleic Peanuts in Shell During Long-Term Storage

Oxidative rancidity is one of the major causes of peanut quality deterioration. The in-shell nut industry's greatest concern is to preserve high quality and extended the shelf life of these products. This research determined the sensory and chemical stabilities of raw in-shell high-oleic and normal-oleic peanuts during long-term storage. In-shell peanuts samples of normal- and high-oleic types were stored at room temperature (23 °C) for 675 days. The quality parameters, like the fatty acid composition, moisture content, free fatty acids (FFA), peroxide value (PV), conjugated dienes (CD), and p-anisidine value (pAV), as well as sensory attributes, were analyzed every 45 days. High-oleic samples showed a 4.36-fold higher oleic acid/linolenic acid (O/L) ratio (O/L = 10.65) than normal-oleic peanuts (O/L = 2.44). FFA, PV, CD, pAV, and oxidized and cardboard flavors increased in all stored samples but especially in normal-oleic peanuts. Conversely, roasted peanutty flavor decreased in all samples during storage but in lower proportion in high oleic peanut samples. The sensory and chemical changes that occurred in unshelled normal- or high-oleic peanut samples were not remarkable, suggesting that the shell may protect peanut kernels against deterioration. However, in-shell high-oleic samples show greater stability and shelf life than normal-oleic peanuts under the studied storage condition.

PRACTICAL APPLICATION

Quality preservation of peanuts is important for the food industry using peanuts as an ingredient. Peanut processors are concerned as to the best ways to preserve peanut quality for long-term storage. Raw high oleic peanuts kept in the shells show better preservation of their sensory and quality properties during storage. In-shell peanuts constitute an appropriate alternative to preserve chemical and sensory properties of this product.

Ethnobotanic, Ethnopharmacologic Aspects and New Phytochemical Insights into Moroccan Argan Fruits

This review summarizes available data on argan fruit botany, geographical distribution, traditional uses, environmental interest, socioeconomic role, phytochemistry, as well as health beneficial effects and examination of future prospects. In particular, ethnomedical uses of argan fruits are carried out throughout Morocco where it has been used against various diseases. Different classes of bioactive compounds have been characterized including essential oils, fatty acids, triacylglycerols, flavonoids and their newly reported acylglycosyl derivatives, monophenols, phenolic acids, cinnamic acids, saponins, triterpenes, phytosterols, ubiquinone, melatonin, new aminophenols along with vitamin E among other secondary metabolites. The latter have already shown a wide spectrum of in vitro, and ex vivo biologicalactivities including antioxidant, anti-inflammatory, anti-diabetic, antihypertensive, anti-hypercholesterolemia, analgesic, antimicrobial, molluscicidal anti-nociceptive and anticancer potential. Argan flesh (pulp) contains a broad spectrum of polyphenolic compounds which may have utility for incorporation into nutraceuticals and cosmeceuticals relevant to the food, cosmetic and health industries. Further research is recommended, especially on the health beneficial effects of the aminophenols.

Insights into the Indian Peanut Genotypes for ahFAD2 Gene Polymorphism Regulating Its Oleic and Linoleic Acid Fluxes

In peanut (Arachis hypogaea L.), the customization of fatty acid profile is an evolving area to fulfill the nutritional needs in the modern market. A total of 174 peanut genotypes, including 167 Indian cultivars, 6 advanced breeding lines and "SunOleic95R"-a double mutant line, were investigated using AS-PCRs, CAPS and gene sequencing for the ahFAD2 allele polymorphism, along with its fatty acid compositions. Of these, 80 genotypes were found having substitution (448G>A) mutation only in ahFAD2A gene, while none recorded 1-bp insertion (441_442insA) mutation in ahFAD2B gene. Moreover, 22 wild peanut accessions found lacking both the mutations. Among botanical types, the ahFAD2A mutation was more frequent in ssp. hypogaea (89%) than in ssp. fastigiata (17%). This single allele mutation, found affecting not only oleic to linoleic acid fluxes, but also the composition of other fatty acids in the genotypes studied. Repeated use of a few selected genotypes in the Indian varietal development programs were also eminently reflected in its ahFAD2 allele polymorphism. Absence of known mutations in the wild-relatives indicated the possible origin of these mutations, after the allotetraploidization of cultivated peanut. The SNP analysis of both ahFAD2A and ahFAD2B genes, revealed haplotype diversity of 1.05% and 0.95%, while Ka/Ks ratio of 0.36 and 0.39, respectively, indicating strong purifying selection pressure on these genes. Cluster analysis, using ahFAD2 gene SNPs, showed presence of both mutant and non-mutant genotypes in the same cluster, which might be due the presence of ahFAD2 gene families. This investigation provided insights into the large number of Indian peanut genotypes, covering various aspects related to O/L flux regulation and ahFAD2 gene polymorphism.

Effect of 12 Weeks High Oleic Peanut Consumption on Cardio-Metabolic Risk Factors and Body Composition

Epidemiological evidence indicates an inverse association between nut consumption and obesity, inflammation, hyperlipidaemia and glucose intolerance. We investigated effects of high oleic peanut consumption vs. a nut free diet on adiposity and cardio-metabolic risk markers. In a randomised cross-over design, 61 healthy subjects (65 ± 7 years, body mass index (BMI) 31 ± 4 kg/m²) alternated either high oleic peanuts (15%-20% of energy) or a nut free diet for 12 weeks. Body composition and mass, waist circumference, C-reactive protein (CRP), lipids, glucose and insulin were assessed at baseline and after each phase. Repeated measures analysis of variance (ANOVA) compared the two diets. Consistent with other nut studies, there were no differences in lipids, CRP, glucose and insulin with peanut consumption. In contrast, some reports have demonstrated benefits, likely due to differences in the study cohort. Energy intake was 10% higher (853 kJ, p < 0.05), following peanut consumption vs. control, attributed to a 30% increase in fat intake (p < 0.001), predominantly monounsaturated (increase 22 g, p < 0.05). Despite greater energy intake during the peanut phase, there were no differences in body composition, and less than predicted increase (0.5 kg) in body weight for this additional energy intake, possibly due to incomplete nutrient absorption and energy utilisation.