Chemical composition of pine nut (Pinus pinea L.) grown in three geographical macrozones in Chile

The Content of Phenolic Compounds and Mineral Elements in Edible Nuts

Edible nuts are an important component of a healthy diet, and their frequent consumption has beneficial impact on human health, including reducing the risk of cardiovascular and neurodegenerative diseases. Moreover, various factors, including cultivar, climate, soil characteristic, storage and treatment have influence on the chemical composition of nuts. Therefore, nine tree nut types and peanuts commonly available on Polish market were evaluated for phenolic profile and mineral elements content. The concentration of individual phenolic compounds, including flavonoids, aromatic acids and caffeic acid phenethyl ester (CAPE) was determined by ultra-high pressure liquid chromatography, while the content of macro-elements and trace minerals was analyzed by atomic absorption spectrometry. The phenolic profile of analyzed nuts substantially varied depending on the type of nut. The highest total content of all analyzed flavonoids was determined in walnuts (114.861 µg/g), while the lowest in almonds (1.717 µg/g). In turn, the highest total content of all tested aromatic acid was determined in pecans (33.743 µg/g), and the lowest in almonds (0.096 µg/g). Epicatechin and cinnamic acid were detected in the highest concentration in tested nuts. Moreover, in examined nuts (except walnuts and Brazil nuts), the presence of CAPE was confirmed. The tested nuts were also characterized by wide variation in element concentrations. Almonds contained high concentration of macro-elements (13,111.60 µg/g), while high content of trace elements was determined in pine nuts (192.79 µg/g). The obtained results indicate that the tested nuts are characterized by a significant diversity in the content of both phenolic compounds and minerals. However, all types of nuts, apart from the well-known source of fatty acids, are a rich source of various components with beneficial effect on human health.

Studies of Phytochemicals, Antioxidant, and Antibacterial Activities of Pinus gerardiana and Pinus roxburghii Seed Extracts

Pine seeds are considered as nonwood forest products (NWFP) with regularly increasing market's demand. They can be eaten in various ways such as roasted or raw. In addition, they are included in various traditional dishes like in cookies, sauces, candies, cakes, breads, and other bakery items and, moreover, for medicinal purposes. GC-MS study is performed to analyze the phytochemical compounds present in the seed extracts of Pinus roxburghii (Chir) and Pinus gerardiana (Chilgoza). In total, 25 compounds were identified each in Chir and Chilgoza. In Chir seeds, abundantly present compounds were 2,4-di-tert-butylphenol (16.6%), followed by ç-Terpinene (9.9%) and cyclohexanol, 4-ethenyl-4-methyl-3-(1-methylethenyl)-, (1à,3à,4á) (9.8%), whereas in Chilgoza seeds, the maximum amount of compound was 1-hexyl-1-nitrocyclohexane (17.3%), followed by phenol, 2,6-bis(1,1-dimethylethyl) (15.4%), and heptadecane, 2-methyl (8.4%). The total phenolic content of Chir seed sample was 1536 ± 4.35 (mg GAE/100 g), whereas in the Chilgoza seed extract was 642.66 ± 2.08 (mg GAE/100 g). The application of RP-HPLC-DAD system revealed that Chir and Chilgoza seeds have maximum quantity of catechin (15.77 ± 0.16 μg/mg and 17.49 ± 0.32 μg/mg, respectively). Both Chir and Chilgoza seed extracts exhibited significant antioxidant (radical scavenging) potential, through H₂O₂ (618.94 ± 21.45 μg/mL and 575.16 ± 19.88 μg/mL) and DPPH (552.60 ± 13.03 μg/mL and 429.15 ± 3.80 μg/mL) assays, respectively. Additionally, a well-known antibacterial potential was also found in both plants' dichloromethane extracts, with 64 to 256 μg/mL of minimum inhibitory concentrations. As a whole, result shows the importance of both plants as a naturally occurring phytochemical source with significant antibacterial and antioxidant activity.

Vitamin E as an essential micronutrient for human health: Common, novel, and unexplored dietary sources

Vitamin E comprises a group of vitamers that includes tocopherols and tocotrienols. They occur in four homologues according to the number and position of methyl groups attached to the chromanol ring. Vitamin E, a liposoluble antioxidant, may participate as an adjuvant in the prevention and treatment of cardiovascular, neurological, and aging-related diseases. Furthermore, vitamin E has applications in the food industry as a natural additive. In this contribution, the most recent information on the dietary sources of vitamin E, including common, novel, and unexplored sources, is presented. Common edible oils, such as those of corn, olive, palm, rice bran, and peanut, represent the most prominent sources of vitamin E. However, specialty and underutilized oils such as those obtained from tree nuts, fruit seeds, and by-products, emerge as novel sources of this important micronutrient. Complementary studies should examine the tocotrienol content of vitamin E dietary sources to better understand the different biological functions of these vitamers.

Microbiomes of commercially-available pine nuts and sesame seeds

Metagenomic analysis of food is becoming more routine and can provide important information pertaining to the shelf life potential and the safety of these products. However, less information is available on the microbiomes associated with low water activity foods. Pine nuts and sesame seeds, and food products which contain these ingredients, have been associated with recalls due to contamination with bacterial foodborne pathogens. The objective of this study was to identify the microbial community of pine nuts and sesame seeds using targeted 16S rRNA sequencing technology. Ten different brands of each seed type were assessed, and core microbiomes were determined. A total of 21 and 16 unique taxa with proportional abundances >1% in at least one brand were identified in the pine nuts and sesame seeds, respectively. Members of the core pine nut microbiome included the genera Alishewanella, Aminivibrio, Mycoplasma, Streptococcus, and unassigned OTUs in the families of Desulfobacteraceae and Xanthomonadaceae. For sesame seeds, the core microbiome included Aminivibrio, Chryseolina, Okibacterium, and unassigned OTUs in the family Flavobacteriaceae. The microbiomes of these seeds revealed that these products are dominated by environmental bacterial genera commonly isolated from soil, water, and plants; bacterial genera containing species known as commensal organisms were also identified. Understanding these microbiomes can aid in the risk assessment of these products by identifying food spoilage potential and community members which may co-enrich with foodborne bacterial pathogens.

Morphological and Chemical Differentiation between Tunisian Populations of Pinus halepensis, Pinus brutia, and Pinus pinaster

The lipid fraction of seeds from different pine species and populations was studied regarding total lipid content, fatty acid profile and vitamin E composition. The investigated seeds contained a high percentage of lipid (13.6 to 31.5 %). Lipid fractions were found to be rich in vitamin E, which varied significantly among species and populations. P. halepensis (Ph-Hn) showed the highest content of vitamin E (256.3 mg/kg of seeds) and the uppermost content of α-tocopherol (44 mg/kg). However, P. halepensis (Ph-Kas) was the richest in γ-tocopherol (204.9 mg/kg). Lipid fractions had a low content of δ-tocopherol (1.2 to 3.6 mg/kg. The highest content of γ-tocotrienol (∼18 %) was determined for P. halepensis (Ph-Dc and Ph-Hn). Thirteen fatty acids were identified by GC-FID with significant variation between the investigated species. The linoleic acid was the major fatty acid followed by oleic acid and palmitic acid. The chemical differentiation among species for the composition of fatty acids and vitamin E was confirmed by PCA. Significant correlations were observed between the content of vitamin E and fatty acids and ecological parameters of P. halepensis populations.

Pickering emulsions stabilized by luteolin micro-nano particles to improve the oxidative stability of pine nut oil

BACKGROUND

Pine oil contains a high percentage of polyunsaturated fatty acids, which make it prone to oxidation. Luteolin (LUT) micro-nano particles with antioxidant properties can be used as stabilizers to form an edible oil-in-water Pickering emulsion to improve the oxidative stability of pine nut oil.

RESULTS

Under optimal preparation conditions, the LUT micro-nano particles and pine nut oil account for about 0.44 and 90.9 g·kg^-1 of the total mass of the emulsion, respectively. The LUT particles in the suspension have a mean particle size of about 479 nm, present a sheet-like structure with a cut surface of 30-50 nm, and can reduce the surface tension of deionized water. In the optimized Pickering emulsion, the emulsion droplets are approximately spherical and have a mean diameter of about 125.6 nm and uniform distribution. The optimized Pickering emulsion droplets can remain stable for up to 2 h in an environment where the pH levels are 7-8.5, ultraviolet B radiation (UVB) irradiation, of less than 5.0 g·kg^-1 , and at a temperature of 80 °C. The stability of the emulsion in simulated digestive fluid changed minimally. In the first 7 days of the accelerated oxidation experiment, LUT micro-nano particles not only successfully protected the integrity of emulsion droplets but also fully inhibited the peroxidation of pine oil.

CONCLUSION

The strong antioxidant properties of LUT micro-nano particles, and the dense protective layer they formed, stabilized the Pickering emulsion successfully. The particles also improved the oxidation stability of pine nut oil. © 2020 Society of Chemical Industry.

Comparative analysis of volatile profiles in two grafted pine nuts by headspace-SPME/GC-MS and electronic nose as responses to different roasting conditions

As an attempt to fulfill the massive demand for pine nuts, two grafted trees were cultivated: grafted Pinus koraiensis on the same scions (PK) and grafted Pinus koraiensis on Pinus sylvestris rootstocks (PKS) trees. Both PK and PKS are acknowledged as important economic trees in the northeastern area of China. This study aimed to compare the volatile compounds and aroma profiles in PK and PKS by Headspace Solid Phase Microextraction (HS-SPME) coupled with Gas Chromatography-Mass Spectrometry (GC-MS) and Electronic nose (E-nose) as responses to different roasting conditions. The results showed that a total of 286 volatile compounds were identified in the PK and PKS samples, which some of them were considered to contribute to the desirable aroma of samples. Abundance of terpenes and aromatic hydrocarbons, such as D-limonene and toluene, were respectively present in both raw PK and PKS. The increasing temperature and duration of roasting significantly decreased terpenes and aromatic hydrocarbons content, while more alkanes/alkenes, acids, and ketones were generated in the medium temperature condition. The late phase of roasting was dominated by aldehydes, furans, furfurals, pyrazines, and pyrroles, for which PKS showed a higher content than PK. The aroma profiles detected by E-nose showed that the influence of roasting time was less at high temperatures than those at low and medium temperatures. This study also highlighted the feasibility of principal component analysis (PCA) combined with HS-SPME/GC-MS and E-nose to discriminate the samples.

Tree Nuts and Peanuts as a Source of Natural Antioxidants in our Daily Diet

Tree nuts and peanuts are healthy foods with a proven track record of helping to reduce the incidence of chronic diseases, most notably cardiovascular disease. At the point of consumption, all nuts contain low moisture and ≥ 50% lipid contents, but this is where similarities end. The levels of key nutrients and bioactives including vitamin C, vitamin E, L-arginine, minerals (such as selenium and zinc), and phenolics can differ markedly. Distinctions in the types and quantities of phenolic constituents for tree nut species, as well as the impact of digestion, will affect the nuts' antioxidant potential in vivo. This work provides some insight into the different types of phenolics found in tree nuts and peanuts, the antioxidant potential of their phenolic extracts using in vitro chemical assays, the effect of thermal processing on the stability of the nuts' endogenous phenolics, and the impact on biomarkers of human health arising from randomized clinical trials. Key biomarkers include measures in the reduction of LDL oxidation as well as increases in the levels of vitamin E and selected phenolic compounds in blood plasma postprandially from those of baseline.

Seed Characteristics and Nutritional Composition of Pine Nut from Five Populations of P. cembroides from the States of Hidalgo and Chihuahua, Mexico

The aim of this study was to analyze the seed characteristics and nutritional composition of five pine nut P. cembroides samples from two Mexican states. Morphometry, proximal composition, phenolic compounds, and antioxidant capacity were determined. Samples differed in several morphometric trails, but important differences were documented between SMCH and JCZH samples from Hidalgo State. JCZH and FMH had the highest contents of water, lipids, protein, flavonoids, and antioxidant activity, while CMCC population from Chihuahua State had presented the highest content of ash and carbohydrates. Morphometry and chemical composition data were subjected to clustering analysis. This analysis showed that SMCH and LFCH from Hidalgo State were well separated from the JCZH and FMH populations from Hidalgo State, which showed a strong similarity between them, while the CMCC from Chihuahua State was the most distant population. Principal components analysis showed that the variables that strongly contributed to PC1 were the antioxidant activity determined by FRAP assay, flavonoids, and water content. These data have provided biochemical markers that could help to establish phylogenetic associations between populations, and also to reveal potentially account as an alternative source for dietary nutrition.

Physical, mechanical, functional and chemical properties of Mexican pink pinion (Pinus pinea L.)

The aim of the study was to evaluate the physical and mechanical properties of the nut and kernel of the Mexican pink pinion (Pinus pinea L.), as well as the physicochemical and functional properties of whole pink pinion meal (WPPM) as well defatted pink pinion meal (DPPM). The length, width, thickness, geometric diameter, arithmetic diameter, sphericity, aspect ratio, surface area, volume, density and hardness of the nut were higher than those of the kernels. The kernel had the highest coefficient of friction, while the nut had the highest angle of repose. WPPM had high fat and protein contents, at 40.5 g/100 g and 41.1 g/100 g, respectively. The major component of DPPM was protein (64.85 g/100 g). The DPPM had higher water absorption, oil absorption, emulsifying and lower gelation capacities (4%), indicating that the meal is a potential source of protein isolates or additives for functional foods and WPPM in food formulations.