Chemical Compositions of Walnut (Juglans regia L.) Oils from Different Cultivated Regions in China

This study is a comprehensive report on the quality of Chinese walnut oil, which enriches the research of oil resources. A total of 16 walnut samples from China were selected, and walnut oils were obtained using the pressing process. The lipid compositions and micronutrient contents were analyzed. The fatty acids corresponded to palmitic acid (3.05–8.25%), oleic acid (12.56–26.03%), linoleic acid (51.21–68.97%), and linolenic acid (6.83–15.01%), and the main triacylglycerols were trilinolein (27.87–39.47%), followed by oleoyl‐linoleoyl‐linolenoyl‐glycerol (17.07–24.18%), dilinoleoyl‐oleoyl‐glycerol (9.65–15.46%), palmitoyl‐dilinoleoyl‐glycerol (5.96–14.98%), and dilinoleoyl‐linolenoyl‐glycerol (6.42–12.43%). In addition, high amounts of micronutrients, including phytosterol, squalene, tocopherol, and total phenolic content, were found in walnut oils ranging from 540 to 1594, 17 to 131, 345 to 1280, and 1.04 to 20.39 mg kg^?1 among different samples, respectively. The differences in the geographical location and climate caused different regions of cultivation, which resulted in the differences in the chemical composition of walnut oil. Further multiple linear regression analyses between oxidative stability indices, fatty‐acid compositions, and micronutrients revealed that linoleic acid (R = ?0.891; P < 0.05), α‐tocopherol (R = 0.713; P < 0.05), and total phenolic content (R = 0.369; P < 0.05) were the main factors that affect the oxidative stability of the walnut oil.     

Composition, Structure and Functional Properties of Protein Concentrates and Isolates Produced from Walnut (Juglans regia L.)

In this study, composition, structure and the functional properties of protein concentrate (WPC) and protein isolate (WPI) produced from defatted walnut flour (DFWF) were investigated. The results showed that the composition and structure of walnut protein concentrate (WPC) and walnut protein isolate (WPI) were significantly different. The molecular weight distribution of WPI was uniform and the protein composition of DFWF and WPC was complex with the protein aggregation. H(0) of WPC was significantly higher (p < 0.05) than those of DFWF and WPI, whilst WPI had a higher H(0) compared to DFWF. The secondary structure of WPI was similar to WPC. WPI showed big flaky plate like structures; whereas WPC appeared as a small flaky and more compact structure. The most functional properties of WPI were better than WPC. In comparing most functional properties of WPI and WPC with soybean protein concentrate and isolate, WPI and WPC showed higher fat absorption capacity (FAC). Emulsifying properties and foam properties of WPC and WPI in alkaline pH were comparable with that of soybean protein concentrate and isolate. Walnut protein concentrates and isolates can be considered as potential functional food ingredients.     

Amino Acid Composition,Molecular Weight Distribution and Gel Electrophoresis of Walnut (Juglans regia L.) Proteins and Protein Fractionations

As a by-product of oil production, walnut proteins are considered as an additional source of plant protein for human food. To make full use of the protein resource, a comprehensive understanding of composition and characteristics of walnut proteins are required. Walnut proteins have been fractionated and characterized in this study. Amino acid composition, molecular weight distribution and gel electrophoresis of walnut proteins and protein fractionations were analyzed. The proteins were sequentially separated into four fractions according to their solubility. Glutelin was the main component of the protein extract. The content of glutelin, albumin, globulin and prolamin was about 72.06%, 7.54%, 15.67% and 4.73% respectively. Glutelin, albumin and globulin have a balanced content of essential amino acids, except for methionine, with respect to the FAO pattern recommended for adults. SDS-PAGE patterns of albumin, globulin and glutelin showed several polypeptides with molecular weights 14.4 to 66.2 kDa. The pattern of walnut proteins in two-dimension electrophoresis (2-DE) showed that the isoelectric point was mainly in the range of 4.8–6.8. The results of size exclusion chromatogram indicated molecular weight of the major components of walnut proteins were between 3.54 and 81.76 kDa.     

Oil chemical variation in walnut (Juglans regia L.) genotypes grown in Argentina

Walnut (Juglans regia L.) oil (WO) from the varieties Chandler, Franquette, Hartley, Lara, Mayette, Serr, Sorrento and Tulare were studied in order to evaluate genotypical variations in fatty acid (FA) and volatile compositions, tocopherol content and oxidative parameters. Oil content was found to range between 71.4 and 73.9%. Oils obtained by pressing presented low acid (0.05–0.22% oleic acid), peroxide (0.05–0.47 meq O₂/kg oil), K₂₃₂, and K₂₇₀ values, and moderate (247–365 µg/g oil) total tocopherol contents. Variations in unsaturated fatty acid contents were between 16.1 and 25.4% (oleic acid), 52.5 and 58.9% (linoleic acid), and 11.4 and 16.5% (linolenic acid). Oxidative stability (OS), as measured by the Rancimat method, was poor (2.64–3.44 h) and it correlated positively with oleic and negatively with linolenic acid contents. In contrast to their low OS, the antioxidant capacity evaluated through the 2,2‐diphenyl‐1‐picrylhydrazyl radical assay showed that the WO analyzed here have good radical‐scavenging activity. Tocopherols appear to be the most important contributors to this biochemical property. The findings connected with volatile composition showed a similar qualitative pattern where aldehydes were present at higher concentration. Most of them seem to come from unsaturated FA mainly through a chemical pathway.     

Hypolipidaemic Effect of Walnut (Juglans regia) Kernel and its Oil in Rats

Walnut (Juglans regia) kernel and its oil were found to reduce serum cholesterol, triglycerides, phospholipids and total lipids in cholesterol bilesalt stressed hypercholesterolaemic rats. Kernel was as effective as its oil (unrefined or refined); thus the efficacy of kernel was due to its oil content having about 70 % polyunsaturated fatty acids. Both unrefined and refined oils having different contents of unsaponifiable matter and sterols behaved in a similar way indicating that unsaponifiable matter and sterol contents of oil were not responsible for their efficacy. There was no difference in faecal cholesterol in animals given vanaspati, walnut kernel or its oil; thus hypolipidaemic effect observed with walnut kernel or its oil could not be attributed to any differences in faecal cholesterol. Serum SGO-T activity of animals of groups given vanaspati, walnut kernel, walnut oil and safflower oil was similar and normal. The blend of vanaspati and walnut oil (1:1) was as effective as walnut kernel and its oil. The study brings to light special value of walnut kernel as a food material in reducing serum lipid constituents.     

Antifungal Activity of Bacillus velezensis CE 100 against Anthracnose Disease (Colletotrichum gloeosporioides) and Growth Promotion of Walnut (Juglans regia L.) Trees

Walnut anthracnose caused by Colletotrichum gloeosporioides is a deleterious disease that severely affects the production of walnut (Juglans regia L.). The aim of this study was to assess the antifungal and growth promotion activities of Bacillus velezensis CE 100 as an alternative to chemical use in walnut production. The crude enzyme from B. velezensis CE 100 exhibited chitinase, protease, and β-l,3-glucanase activity and degraded the cell wall of C. gloeosporioides, causing the inhibition of spore germination and mycelial growth by 99.3% and 33.6% at 100 µL/mL, respectively. The field application of B. velezensis CE 100 culture broth resulted in a 1.3-fold and 6.9-fold decrease in anthracnose disease severity compared to the conventional and control groups, respectively. Moreover, B. velezensis CE 100 produced indole-3-acetic acid (up to 1.4 µg/mL) and exhibited the potential for ammonium production and phosphate solubilization to enhance the availability of essential nutrients. Thus, field inoculation of B. velezensis CE 100 improved walnut root development, increased nutrient uptake, enhanced chlorophyll content, and consequently improved total biomass by 1.5-fold and 2.0-fold compared to the conventional and control groups, respectively. These results demonstrate that B. velezensis CE 100 is an effective biocontrol agent against anthracnose disease and a potential plant growth-promoting bacteria in walnut tree production.     

Evaluation of antimicrobial and dyeing properties of walnut (Juglans regia L.) green husk extract for cosmetics

Walnut green husk is one of the main waste products from walnut and could be used as a source of natural dyeing compounds such as juglone. The present study was conducted to evaluate the effective use of walnut green husk extract as a natural hair dye. Dyeing properties, fastness and antimicrobial behaviours of dyed hair and also a skin irritation test for natural hair dye on rat skin were examined. When the extract was mixed with ascorbic acid as a developer, ferrous sulphate as a mordant, and Aloe vera extract used as a secondary mordant and also a cosmetic ingredient, the reaction resulted in a dark‐brown colour on hair samples. The dyed hair exhibited appropriate colour strength having excellent morphology for a hair surface coated with dye molecules. In addition, the dyed hair possessed good resistance to washing and daylight fastness, without any irritant properties as shown in a rat model, although high concentrations of iron‐based mordant may be problematic for long‐term usage. This paper also suggests the use of natural mordants such as lactic and oxalic acids to avoid any probable risks. Walnut green husk extract was an appropriate natural hair dyeing agent in practice and showed maximum antimicrobial activity compared with semi‐synthetic and commercial hair dyes. The results demonstrated that walnut green husk can be used as an economical, valuable, eco‐friendly and safe source of dyeing and antimicrobial agents for cosmetic products.     

Fracture toughness of walnut particles (Juglans regia L.) and coconut fiber‐reinforced hybrid biocomposite

The rectangular specimens with an edge crack were subjected to symmetric three‐point bending and asymmetric four‐point bending to determine the mode I and mode II fracture toughness of the walnut particle and coconut fiber‐reinforced biocomposite. Epoxy resin was used as matrix material and 10 wt% of coconut fiber and 20 wt% of walnut shell particle were used as reinforcing materials. The mode I and mode II fracture toughness and mechanical tests were conducted on a servo hydraulic universal testing machine and the results were analyzed and discussed. POLYM. COMPOS., 36:167–173, 2015. © 2014 Society of Plastics Engineers     

Novel Insights into Anthocyanin Metabolism and Molecular Characterization of Associated Genes in Sugarcane Rinds Using the Metabolome and Transcriptome

Saccharum officinarum (sugarcane) is the fifth major cultivated crop around the world. Sugarcane rind is a promising source for anthocyanin pigments; however, limited information is available on the anthocyanin and its biosynthesis in sugarcane rinds. In this study, we have quantified 49 compounds including 6 flavonoids and 43 anthocyanins in the rind of 6 sugarcane cultivars by using LCMS/MS approach. Thirty of them were quantified for the first time in sugarcane. The 43 anthocyanins included 10 cyanidin (Cya), 11 pelargonidin (Pel), 9 peonidin (Peo), 5 malvidin (Mal), 4 delphinidin (Del), and 4 petunidin (Pet) metabolites. High contents of Cya derivatives were observed in the rind of YT71/210 (dark purple rind), such as cya-3-O-(6-O-malonyl)-glu 1283.3 µg/g and cya-3-O-glu 482.67 µg/g followed by ROC22 (red rind) 821.3 µg/g and 409 µg/g, respectively, whereas the YT93/159 (green rind) showed a minimum level of these compounds. Among six cultivars, ROC22 rind has high levels of Peo derivatives such as peo-3-O-glu (197 µg/g), peo-3-O-(6-O-malonyl)-glu (69 µg/g) and peo-3-O-(6-O-p-coumaryl)-glu (55.17 µg/g). The gene expression analysis revealed that some genes, including a MYB(t) gene, were highly associated with the color phenotype. Thus, we cloned and overexpressed the gene in Arabidopsis and found the pinkish brown color in the hypocotyl of all transgenic lines compared with the wild type. Hence, we have quantified a wide range of anthocyanins in major sugarcane cultivars, reported many new anthocyanins for the first time, and concluded that Cya and Peo derivatives are the major contributing factor of dissimilar colors in sugarcane. The finding and the verification of a novel MYB gene involved in anthocyanin biosynthesis have demonstrated that our study was very valuable for gene discovery and genetic improvement of sugarcane cultivars to harvest high anthocyanin contents.