Acid In Kernels Research Articles

The identification and expression analysis of walnut Acyl-ACP thioesterases.

Walnuts (Juglans regia L.), renowned for their nutritional potency, are a rich source of unsaturated fatty acids. Their regular intake plays a pivotal role in health maintenance and recuperation from a myriad of ailments. Fatty acyl-acyl carrier protein thioesterases, which orchestrate the hydrolysis of acyl-ACP thioester bonds, thereby yielding fatty acids of varying chain lengths, are instrumental in augmenting plant fatty acid content and modulating the balance between saturated and unsaturated fatty acids. Despite some investigative efforts into the synthesis and metabolic pathways of fatty acids in walnuts, our comprehension of Fat in walnuts remains rudimentary. This research undertook a comprehensive characterization of the JrFat family, predicated on the complete genome sequence of walnuts, leading to the identification of 8 JrFat genes and an exploration of their protein physicochemical properties. Utilizing Arabidopsis and soybean Fat genes as outgroups, JrFat genes can be categorized into 5 distinct subgroups, three of which encompass a pair of homologous gene pairs. These genes have demonstrated remarkable conservation throughout the evolutionary process, with highly analogous conserved base sequences. The promoter region of JrFats genes predominantly harbors light response and plant hormone response regulatory elements, with no discernible disparity in promoter elements among different JrFats. Predictive analyses indicate that JrFats proteins engage extensively with walnut fatty acid synthesis and metabolism-associated proteins. qRT-PCR analysis reveals an initial surge in the expression of JrFats during the development of walnut kernels, which either stabilizes or diminishes following the hard core period. Homologous gene pairs exhibit analogous expression patterns, and the expression trajectory of JrFats aligns with the dynamic accumulation of fatty acids in kernels. The expression of JrFatA2 exhibits a strong correlation with the content of Alpha-linolenic acid, while the expression of JrFatB2 is inversely correlated with the content of two saturated fatty acids. Collectively, these findings enrich our understanding of fatty acid synthesis and metabolism in walnuts and furnish gene resources for enhancing the content and ratio of fatty acids in walnuts.

Bioactive Compounds and Antioxidant Activities in Different Fractions of Mango Fruits (Mangifera indica L., Cultivar Tommy Atkins and Keitt).

This study aims to describe and compare the distribution of bioactive compounds, the fatty acids profiles, and the TEAC hydrophilic and lipophilic antioxidant activities in different fruit fractions (pulp, peel, and kernel) of two mango cultivars (Tommy Atkins and Keitt). All fractions are sources of health-promoting bioactive compounds. Regardless of cultivars, pulp had the highest content of phytosterols (~150 mg/100 g dw), peels ranked first for pentaciclic triterpenes (from 14.2 to 17.7 mg/100 g dw), tocopherols, carotenoids, and chlorophylls, and kernels for phenolic compounds (from 421.6 to 1464.8 mg/100 g dw), flavonoids, condensed tannins, as well as hydrophilic and lipophilic antioxidant activities. Differences between the two cultivars were evidenced for ascorbic acid, which showed the highest levels in the peels and kernels of Keitt and Tommy Atkins fruits, respectively. Similarly, the concentration of dehydroascorbic acid was higher in the pulp of Tommy Atkins than Keitt. The highest percentage of saturated fatty acids was observed in pulp (~42%) and kernels (~50%), monounsaturated fatty acids in kernels (up to 41%), and polyunsaturated fatty acids in peels (up to 52%). Our results add information to the current knowledge on nutraceuticals’ distribution in different fractions of mango fruit, supporting its consumption as a healthy fruit and suggesting the great potential value of peels and kernels as sources of novel ingredients. Indeed, mango by-products generated during agronomic-to-industrial processing not only causes a significant environmental impact, but economic losses too. In this scenario, boosting research on conventional recovery methods offers eco-friendly solutions. However, green, novel biorefinery technologies may offer eco-friendly and profitable solutions, allowing the recovery of several more profitable by-products, sustaining their continuous growth since many bioactive compounds can be recovered from mango by-products that are potentially useful in the design of innovative nutraceutical, cosmeceutical, and pharmaceutical formulations.

Fatty Acid Profiling in Kernels Coupled with Chemometric Analyses as a Feasible Strategy for the Discrimination of Different Walnuts

Walnuts have high oil content in their kernels, and they have attracted considerable attention in the food, beverage, nutrient, and health fields because of their delicious taste and potential health benefits. Fatty acid profiles of kernels vary depending on walnuts species, ontogenic variations, and planting environments. To determine the key indicators that can be used to distinguish different walnuts using chemometric analyses, the fatty acid compositions and contents of 72 walnut samples were measured and evaluated. Three fatty acids, oleic acid (21.66%), linoleic acid (56.40%), and linolenic acid (10.50%), were the most common fatty acid components in the kernels. Palmitic acid and linolenic acid in kernels were found to be indicators to rank the walnuts into five levels. Three groups were identified based on of several chemometrics. Oleic acid in kernels was typical fatty acid that could be used to distinguish three walnut groups based on the results of discriminant analysis, while oleic acid and linoleic acid were key differential fatty acids on the discrimination of each group based on the result of orthogonal partial least squares discriminant analysis. This study provides information on how to classify walnuts from different geographical locations based on kernel fatty acid profiling and provides an approach to identify possible adulterations in walnuts on the markets. Moreover, the results are potentially relevant to quality assessments of walnuts.

Walnut (Juglans regia L.) Volatile Compounds Indicate Kernel and Oil Oxidation.

Kernel oxidation susceptibility and pellicle darkening are among the biggest concerns regarding walnut quality. Monitoring oxidation is crucial to preserve quality from production to consumption. Chemical oxidation parameters (peroxide value and UV absorbances), fatty acid profile, tocopherols, phenols, and volatiles in ‘Chandler’ and ‘Howard’ kernels were studied at different time points during 28 weeks of storage to evaluate potential oxidation markers. During storage, peroxide value, UV absorbances, and volatiles concentration increased; oxidative stability, phenols, and tocopherols decreased, while fatty acid profile was unaffected. ‘Chandler’ had a lower peroxide value, K232, and K268; and higher kernel and oil oxidative stability compared to ‘Howard’. Phenols and tocopherols decreased 1.2-fold in ‘Chandler’ and 1.3-fold in ‘Howard’. Using multivariate analysis, samples were discriminated in three groups according with their oxidative levels. Increases of volatiles in oil and kernel were associated with higher oxidative levels. Pentanal, 2-methylpropanal, hexanal, (E)-2-pentenal, 3-octanone, octanal, (Z)-2-penten-1-ol, hexanol, (E)-2-octenal, 1-octen-3-ol, benzaldehyde, (E,E)-2,4-nonadienal, and hexanoic acid in kernels were adequate at distinguishing oxidation levels and as oxidative markers in walnuts. Kernel volatiles is a useful measurement for walnut oxidation during storage without any prior fat extraction.

Phenolic acids in kernels of different coloured-grain wheat genotypes

The content of free, conjugated and bound phenolic acids in 12 wheat (Triticum aestivum L.) genotypes of 4 different grain colours (standard red, yellow endosperm, purple pericarp and blue aleurone) from 2-year field trial was analysed in the present study. Significant increase (8%) in the total phenolic acid content was observed in the dryer year 2017. Five phenolic acids (ferulic, sinapic, p-coumaric, vanillic and 4-hydroxybenzoic) and cis-isomers of ferulic and sinapic acid were determined by HPLC-DAD (high-performance liquid chromatography with a diode-array detector) in grain samples. The total phenolic acid content of coloured wheat groups varied: blue aleurone > purple pericarp > yellow endosperm > red colour (798 > 702 > 693 > 599 µg/g). The fraction of bound phenolic acids was the major contributor to the total phenolic acid content (91.7%) with ferulic acid predominating (85.2%). Conjugated phenolic acids accounted for 7.9% of the total with sinapic and ferulic acid predominating (47.6% and 19.9%). The composition of individual phenolic acids was similar within these two fractions. The remaining 0.4% was represented by the fraction of free phenolic acids in which the phenolic acid profile varied among the individual coloured groups. Ferulic acid prevailed in red and yellow wheats, vanillic in blue and p-coumaric in purple wheats.

Analysis of the peanut transgenic offspring with depressing AhFAD2 gene

The delta-12 fatty acid desaturase (Δ¹² FAD or FAD2) is a key enzyme that catalyzes oleic acid to linoleic acid by dehydrogenation at Δ¹² position of fatty acid carbon chain. In peanut, reduction or loss of FAD2 activity could enhance the relative content of oleic acid in kernels, and improve the quality and oxidation stability of peanut kernels and products. RNA interference (RNAi) technology could lead to non-expression or down-regulated expression of AhFAD2 gene. We constructed two RNA interference expression vectors with the inverted repeat sequence of partial AhFAD2 gene, which were driven separately by cauliflower mosaic virus (CaMV) 35S promoter or soybean agglutinin lectin seed-specific promoter. Homozygous transgenic lines carrying the two constructs stably in genetics were developed by peanut genetic transformation. There were no significant differences between the transgenic lines and the control through investigating the main agronomic traits. We analyzed the transcriptional level expression of AhFAD2 gene in transgenic lines and the control by real-time fluorescence quantitative PCR (qRT-PCR). The results suggested that the target genes of transgenic lines were likely suppressed by RNA interference, but showed different transcriptional levels in different peanut transgenic lines. Compared with untransformed lines, the resulting down-regulation of AhFAD2 gene resulted in a 15.09% or 36.40% increase in oleic acid content in the seeds of transformed HY23 and FH1 lines respectively, and the content of linoleic acid decreased by 16.19% or 29.81%, correspondingly, the ratio of oleic acid and linoleic acid (O/L) improved by 38.02%, 98.10%. The oleic acid content had significant differences between the two transformation constructs, and also among different transgenic lines. Moreover, the inhibition effect of RNAi was more obvious in the transgenic lines with FH1 as the receptor, and with transformation structure driven by seed specific promoter. The suppressed expression of AhFAD2 gene enabled the development of peanut fatty acid, which indicated that RNA interference would be a reliable technique for the genetic modification of peanut seed quality and the potential for improvement of other traits as well.

Effects of long-term fertilizer applications on peanut yield and quality and plant and soil heavy metal accumulation

The status of essential and potentially toxic trace elements in soils and crops can be affected by long-term fertilization practices. This study aimed to investigate changes in peanut (Arachis hypogaea L.) yield and kernel quality, and changes in copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) concentrations in soil and peanut kernels after 16 years of continuous cropping with different fertilization treatments. Five fertilization treatments were applied at a red soil site in Southeast China: chemical fertilizer (F) containing nitrogen, phosphorus, and potassium, F + trace elements (FT), pig manure (M), M + effective microorganisms (MB), and MB + trace elements (MBT). Properties of soil and pig manure, heavy metal contents in soil and peanut kernels, and the compositions of amino and fatty acids in kernels were determined. Application of pig manure significantly increased peanut biomass, kernel yield, and crude protein and total amino acid contents in kernels, but led to higher amounts of Cu, Zn, and Cd in soil and higher amounts of Zn and Cd in peanut kernels compared with that of chemical fertilizer. There should be greater concern about potential kernel Cd and Zn contaminations resulting from long-term application of pig manure contaminated with potentially toxic metals as an organic fertilizer.

Composition of amino acids, fatty acids and dietary fibre monomers in kernels of Adansonia digitata and Sclerocarya birrea

There is increasing demand for sources of energy and non-meat protein with balanced amino acid profiles worldwide. Nuts are rich in protein and essential amino acids, and have a high energy value due to their high fat content. Kernels from two wild fruits in Mozambique, Adansonia digitata and Sclerocarya birrea, were selected for this study to determine their amino acid and fatty acid composition, as well as the monomeric composition of their dietary fibre. The fat content in Adansonia digitata kernels was around 32% and in Sclerocarya birrea kernels 49%. Both kernels were rich in unsaturated fatty acids. The dominating fatty acids in Adansonia digitata kernels were palmitic, linoleic and oleic acid; varying from 25.7% to 34.9% of the total fatty acids content. In Sclerocarya birrea kernels the main fatty acid was oleic acid, 72.4%. The Adansonia digitata kernels contained the two essential fatty acids linoleic (around 30%) and linolenic acid (2%). Sclerocarya birrea kernels contained linoleic acid (around 7%). The protein content in Adansonia digitata kernels was 35% and in Sclerocarya birrea kernels 29%. Glutamic acid was the most abundant amino acid, comprising more than 20% of the protein in both kernels. The contents of essential amino acids in the kernels were compared with the requirements stated by the WHO, and the findings indicate that Adansonia digitata and Sclerocarya birrea kernels can provide good, cheap sources of protein, especially when combined with foods with high lysine content. Regarding the dietary fibre fractions, the main constituent in the insoluble fraction of Adansonia digitata kernels was glucose, while in the soluble fraction arabinose was the dominating component. In kernels of Sclerocarya birrea, uronic acids constituted more than 90% of both dietary fibre fractions. The results of this study suggest that intake of these kernels can help providing a great part of the fatty acids and amino acids required in the daily diet, especially for people living in rural areas of Mozambique. The data could be used for intake estimates, and to encourage increased consumption and utilization of these kernels. (Less)

Efficient bioconversion of palm acid oil and palm kernel acid oil to poly(3-hydroxybutyrate) by Cupriavidus necator

Efficient bioconversion of palm oil by-products to green materials serves as a prominent way to overcome wastage. Generally, major palm oil by-products such as palm acid oil (PAO) and palm kernel acid oil (PKAO) are used for animal feed. This pioneer study investigated the ability of Cupriavidus necator H16 (ATCC 17699) (formerly Ralstonia eutropha) to biologically convert these by-products to poly(3-hydroxybutyrate) [P(3HB)]. P(3HB) was synthesized when PAO or PKAO was fed as the sole carbon source. However, it was found that PKAO is superior with respect to higher amount of P(3HB) accumulation in 48 h (85 wt% of the dry cell mass). In addition, important culture parameters were identified, such as nitrogen sources and ratio of culture volume to flask volume, which significantly affected the P(3HB) content. The nitrogen concentration in the culture medium is very crucial in promoting the biosynthesis of P(3HB). The highest P(3HB) yield (3.1 g/L) was initiated at 4 mmol/L of urea. Less than 0.4 g/L of P(3HB) was obtained when 30.0 mmol/L or higher urea concentrations were used. This study has identified a suitable process to produce high P(3HB) yield from major palm oil by-products. It is also demonstrated that C. necator H16 has suitable metabolic pathways that allow the conversion of palm oil by-products to P(3HB) effectively. Hereby, surplus palm oil by-products can be converted to a relatively high-value and sustainable product.Key words: poly(3-hydroxybutyrate), palm oil, palm acid oil, palm kernel acid oil, Cupriavidus necator.

Selection and characterization of a 5-methyltryptophan resistant mutant in Zea mays L.

A maize plant resistant to 5-methyltrytophan (5MT) was selected from M2 seeds (Zea mays L. Danggin, inbred line) originating from ears treated with ethylmethane sulfonate (0.2%) at 6 hr after self-pollination. Genetic analysis of the progeny of plants selected from a medium containing 50 ppm 5MT showed that 5MT resistance was inherited as a single dominant nuclear gene. This resistance was also expressed in callus and seedling. Analysis of the free amino acids in kernels and calli showed that homozygous resistant plants (MR1) contained higher levels of total free amino acids than sensitive plants and calli. In particular, the their kernels the levels of tryptophan, threonine and serine were, respectively, 4.5, 5.9 and 6.3 times higher than those of the sensitive plants. From the results, it may be expected that mutants resistant to amino acid anologs will be useful not only for studying amino acid biosynthesis but also for improving the nutritional quality of maize.

Antimutagenic activities of hexane extracts of the fruit extract and the kernels of Prunus mume Sieb. et Zucc

Antimutagenic activities of hexane extracts obtained from the fruit extract (UE) and the Kernels (KE) of P. mume were examined. These extracts showed inhibitory activities to known mutagens, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide, benzo[alpha]pyrene and aflatoxin B1 in the Ames assay using Salmonella typhimurium TA100 and TA98 strains. The UE and KE fractions were then separated by silicic acid column chromatography with a stepwise elution method using ether-hexane. The location of the active substances in the fractions was also determined by thin-layer chromatography. Consequently, it was found that the effective substances for the desmutagenicity were fatty acids, and identified by gas liquid chromatography, mainly as oleic acid, linoleic acid and linolenic acid in UE, and mainly as oleic acid and linoleic acid in KE, respectively.

Regulation of Embryo Dormancy by Manipulation of Abscisic Acid in Kernels and Associated Cob Tissue of Zea mays L. Cultured in Vitro

Sectors of Zea mays cobs, with and without kernels were cultured in vitro in the presence and absence of fluridone. Cultured kernels, cob tissue, and embryos developed similarly to those grown in the field. Abscisic acid (ABA) levels in the embryos were evaluated by enzyme-linked immunosorbant assay. ABA levels in intact embryos cultured in the presence of fluridone were extremely low and indicate an inhibition of ABA synthesis. ABA levels in isolated cob tissue indicate that ABA can be produced by cob tissue. Sections containing kernels cultured in the presence of fluridone were transferred to medium containing fluridone and ABA. Dormancy was induced in more than 50% of the kernels transferred from 13 to 15 days after pollination, but all of the kernels transferred at 16 days after pollination or later were viviparous. ABA recovered from kernels that were placed in medium containing fluridone and ABA suggest that ABA can be transported through the cob tissue into developing embryos and that ABA is required for induction of dormancy in intact embryos.

Inheritance and expression of lysine plus threonine resistance selected in maize tissue culture

Selection for resistance to growth inhibition by lysine plus threonine in equimolar concentrations (LT) in tissue cultures of maize yielded a stable resistant line, LT19. Genetic analysis of progeny of plants regenerated from LT19 showed that LT resistance was inherited as a single dominant nuclear gene, temporarily designated Ltr(*)-19. Tissue cultures initiated from resistant embryos required 5-10 times higher levels of LT to inhibit growth than did cultures from LT-sensitive embryos. LT resistance in Ltr(*)-19 was expressed as much reduced inhibition of root and shoot growth in the presence of LT. The free pool of threonine was increased 6 times in cultures initiated from immature embryos of LT-resistant plants, and 75-100 times in kernels homozygous for Ltr(*)-19, as compared to cultures and kernels from LT-sensitive embryos and plants, respectively. Overproduction of free threonine increased the total threonine content in homozygous Ltr(*)-19 kernels by 33-59%. The results demonstrate that LT resistance selected with tissue culture methods is heritable and is expressed in cultures, seedlings, and kernels. Furthermore, they demonstrate a method to obtain amino acid-overproducer mutants in maize, which have the potential to increase substantially specific amino acids in kernels. The capability to increase specifically the nutritionally limiting amino acid(s) could have important nutritional implications for the grain of cereals and other crops.