Chemical composition and oxidative stability of eleven pecan cultivars produced in southern Brazil

Pecan (Carya illinoinensis (Wangenh.) K. Koch) nuts as an emerging source of protein: extraction, physicochemical and functional properties

BACKGROUND

The increasing demand for sustainable alternatives to traditional protein sources, driven by population growth, underscores the importance of protein in a healthy diet. Pecan (Carya illinoinensis (Wangenh.) K. Koch) nuts are currently underutilized as plant-based proteins but hold great potential in the food industry. However, there is insufficient information available on pecan protein, particularly its protein fractions. This study aimed to explore the physicochemical and functional properties of protein isolate and the main protein fraction glutelin extracted from pecan nuts.

RESULTS

The results revealed that glutelin (820.67 ± 69.42 g kg-1) had a higher crude protein content compared to the protein isolate (618.43 ± 27.35 g kg-1), while both proteins exhibited amino acid profiles sufficient for adult requirements. The isoelectric points of protein isolate and glutelin were determined to be pH 4.0 and pH 5.0, respectively. The denaturation temperature of the protein isolate (90.23 °C) was higher than that of glutelin (87.43 °C), indicating a more organized and stable conformation. This is further supported by the fact that the protein isolate had a more stable main secondary structure than glutelin. Both proteins demonstrated improved solubility, emulsifying, and foaming properties at pH levels deviating from their isoelectric points in U-shaped curves. Compared to the protein isolate, glutelin displayed superior water and oil absorption capacity along with enhanced gelling ability.

CONCLUSION

The protein isolate and glutelin from pecan nuts exhibited improved stability and competitive functional properties, respectively. The appropriate utilization of these two proteins will support their potential as natural ingredients in various food systems. © 2024 Society of Chemical Industry.

Evaluation of Lipid Quality in Fruit: Utilizing Lipidomic Approaches for Assessing the Impact of Biotic Stress on Pecans (Carya illinoinensis)

There is a scarcity of data on how the lipid composition of oily seeds changes in response to biotic stress. Yellow peach moth (Conogethes punctiferalis) has caused massive economic losses on the pecan (Carya illinoinensis) industry. Lipidomics is used in this study to determine the lipid composition of pecan and how it changes in response to insect attack. Pecan had 167 lipids, including 34 glycerolipids (GL), 62 glycerophospholipids (GP), 17 fatty acyls (FA), 41 sphingolipids (SP), and 13 saccharolipids (SL). The effects of biotic stress on lipids, particularly GL and GP, were significant. Biotic stress significantly reduced the lipid content of chains longer than 48. Forty-four significantly different lipids were discovered as potential biomarkers for distinguishing non-infected pecans from infested pecans. In addition, we used bioinformatics to identify the five most important metabolic pathways in order to investigate the processes underlying the changes. Our discoveries may offer valuable insights for enhancing pecan production in the future and contribute novel perspectives towards enhancing the nutritional value of pecans.

Comparison of the metabolic profile of pecan nuts cultivars [Carya illinoinensis (Wangenh.) K. Koch] by NMR spectroscopy

Pecan nuts (Carya illinoinensis (Wangenh.) K. Koch) contain the highest number of phytochemicals of all nuts, are a natural source of unsaturated fatty acids and other nutrients and can be considered an important addition to the Mediterranean diet al.though several studies have been carried out on pecans, employing several analytical techniques, no systematic study of the metabolic profile is available in literature. In this study, the metabolic profile of pecan nuts of three different cultivars was analysed by Nuclear Magnetic Resonance Spectroscopy. The cultivars compared were Wichita, Stuart, and Sioux, all grown in Italy in the same pedoclimatic conditions. 31 metabolites were identified and 28 were quantified and the three species were differentiated based on multivariate PCA analysis. The differences among them, and the levels of scutellarein and GABA, in particular, were attributed to the adaptation of the plants to the climate in their original areas.

Lipidomic and comparative transcriptomic analysis of fatty acid synthesis pathway in Carya illinoinensis embryo

Pecan (Carya illinoinensis (Wagenh.) K. Koch) is an important oilseed nut and is rich in fatty acids (FAs) and flavonols. Pecan FA has significantly edible, industrial and clinical value. To investigate the dynamic patterns and compositions of FA, and the molecular mechanism that controls FA accumulation in pecan, lipidomic and transcriptomic analyses were performed to determine lipid profiles and gene expression in pecan's FA biosynthesis pathway. In the present study, compared with cultivars 'Caddo' and 'Y-01', 'Mahan' formed larger and heavier embryos and accumulated higher oil content. Lipidomic analysis showed that FA and (O-acyl)-1-hydroxy FA contents were higher in 'Mahan' at the mature stage. Based on full-length and comparative RNA-Seq, differential expression gene enrichment analysis revealed that many functional genes participated in the pathways of 'fatty acid biosynthesis', 'fatty acid metabolism' and 'linoleic acid metabolism'. High FA accumulation model from 'Mahan' demonstrated that key enzyme-encoding genes played an important role in regulating FA biosynthesis. Co-expression module analysis indicated that several transcription factors (TFs; MYB, TCP, bHLH, Dof, ERF, NAC) were involved in FA accumulation by regulating the expression of functional genes, and real-time quantitative PCR verification proved that these TFs had a high correlation with the pecan FA accumulation pattern. These findings provided an insight into the molecular mechanism of FA accumulation in C. illinoinensis embryo, which contributes to pecan oil yielding and pecan molecular breeding.

Optimization of Ultrasound-Assisted Extraction of Dietary Fiber from Yellow Dragon Fruit Peels and Its Application in Low-Fat Alpaca-Based Sausages

The main objective of this study was to optimize the extraction of dietary fiber (insoluble dietary fiber and soluble dietary fiber) and degree of esterification from yellow dragon fruit peels using ultrasound-assisted extraction. Additionally, the study aimed to investigate the potential application of this fiber as a fat replacement in alpaca-based sausages. The optimization process for extracting dietary fiber and degree of esterification involved considering various factors, including the liquid-to-solid ratio, pause time, and total ultrasound application time. A Box-Behnken design consisting of 15 treatments was employed to determine the optimal levels for ultrasound-assisted extraction. The optimized conditions were found to be a liquid-to-solid ratio = 30 mL/g, pause time = 1 s, and total ultrasound application time = 60 min, which resulted in the highest values of insoluble dietary fiber (61.3%), soluble dietary fiber (10.8%), and the lowest value of degree of esterification (39.7%). The predicted values were validated against experimental data and showed no significant differences (p > 0.05). Furthermore, a completely randomized design was utilized to assess the effect of dietary fiber on replacing fat content during the production of alpaca-based sausages. The findings revealed that up to 78% of the fat content could be successfully replaced by soluble dietary fiber obtained from yellow dragon fruit peels when compared to high-fat sausages. Additionally, experimental sausages using soluble dietary fiber showed similar (p > 0.05) quality characteristics, such as hardness (24.2 N), chewiness (11.8 N), springiness (0.900), cohesiveness (0.543), redness (a* = 17.4), and chroma values (20.0), as low-fat commercial sausages.

Higher CO2 during controlled atmosphere storage of unshelled 'Barton' pecans or carnauba wax coating: Effect on the quality after long-term storage at two temperatures

Pecan nuts, a healthy food, have shown an increased demand for consumption. Therefore, there must be a certain level of care to avoid quality losses, which are primarily influenced by storage conditions and time. This study evaluates the effects of long-term controlled atmosphere (CA) storage with low O₂ partial pressure (pO₂ - 2 kPa), combined or not with high CO₂ (pCO₂ - 40 or 80 kPa), carnauba wax coating (CW), and ambient atmosphere (AMB; control) at 10 and 20 °C, on unshelled 'Barton' pecan nut quality. Color, water activity (A_w), moisture content (MC), and oxidation markers, such as peroxide value (PV), acidity value (AV), TBARS, and volatile compounds (VC) were evaluated. Storage up to twelve months at 10 °C and with CA (regardless of the temperature) ensured higher luminosity and color parameter b* ("golden") and a lower a* parameter ("reddish"). The MC ranged from 2.8 to 3.6%, irrespective of storage conditions, for up to twelve months, which is suitable. The AMB at 10 °C ensured lower AV, TBARS, and PV compared to the CW treatment. Furthermore, CA with low pO₂ and high pCO₂, even at 20 °C, guaranteed lower AV, TBARS, and PV. Storage at 20 °C increased characteristic VCs of lipid oxidation (aldehydes, acids, alcohols, ketones, lactones, and esters, especially with CW coating). However, all conditions at 10 °C and with pCO₂ (even associated at 20 °C) reduced the presence of these VCs. The CW used as a coating on the pecans did not show satisfactory results and should not be recommended for pecan storage at these applied conditions. Our findings showed that low pO₂ and high pCO₂ maintain better pecan quality than O₂ ambient (20 kPa), even at temperatures above refrigeration (20 °C). Nevertheless, there were no significant differences between 40 and 80 kPa CO₂.

Metabolomics and Transcriptomics Analyses Reveal Regulatory Networks Associated with Fatty Acid Accumulation in Pecan Kernels

Pecans are a globally important tree nut crop. Pecan nuts are rich in fatty acids (FAs), proteins, and flavonoids in addition to thiamine and numerous micronutrients. Although several of these nutriments have been studied in this plant, the comprehensive metabolite variations and molecular mechanisms associated with them have not been fully elucidated. In this study, untargeted metabolomics and transcriptomics were integrated to reveal the metabolite accumulation patterns and their associated molecular mechanisms during pecan kernel development. In total, 4260 (under positive mode) and 2726 (under negative mode) high quality features were retained. Overall, 163 differentially accumulated metabolites were identified. Most components were classified into the categories "organic acids and derivatives" and "lipids and lipid-like molecules." The accumulation patterns of amino acids, FAs, carbohydrates, organic acids, vitamins, flavonoids, and phenylpropanoids alongside embryo development were determined. Furthermore, transcriptomes from four pecan kernel developmental stages were used to assess transcript expression levels. Coexpression analyses were performed between FAs and their related genes. This study provides a comprehensive overview of the metabolic changes and regulations during pecan kernel development. We believe that the identification of nutriment accumulation trends and hub genes associated with the biosynthesis of the components will be valuable for genetically improving this plant.

Consumer Hedonic Ratings and Associated Sensory Characteristics and Emotional Responses to Fourteen Pecan Varieties Grown in Texas

Pecan is one of the top five most widely consumed tree nuts, and pecan nut quality is a major factor for consideration in breeding better pecan cultivars for use by producers. However, the pecan industry faces a hurdle to evaluate its nutmeat taste, and there has so far been limited evaluation of consumer attitudes toward pecan nutmeat. This study aimed to investigate the consumer (n = 198) hedonic rating, diagnostic sensory attribute intensity, and emotional response for 14 pecan samples, consisting of native/seedling and improved varieties. The results showed all kernels received positive hedonic scores (>5, 9-point hedonic scale) for overall acceptance and the acceptability of size, interior color, typical-pecan flavor, and raw-nut flavor. The primary sensory attributes (intensities > 5.0, 0−10 line scale) were typical-pecan and raw-nut flavors, followed by buttery flavor, sweetness, and astringency. Kernel off-flavors were not perceived in general. For 20 emotion-associated terms, the intensity of the satiating effect was medium, while the energizing effect was lower. The major emotional responses were healthy, satisfied, and comfort, followed by calm, interested, premium, and relaxed. Kernel variety difference was significant (p ≤ 0.05) for all these measured variables. Consumer overall acceptance toward pecan kernels was driven by the acceptability of flavor and interior color, flavor intensities, no off-flavors, and positive emotional responses; kernel size was not an impactful factor. The six most preferred varieties were 86TX2-1.5, Pawnee, Barton, 1997-09-0012, 1991-01-0026, and Harris Super. This study is the first to use consumer input to assess nut quality and consumption preference and will be foundational to ongoing breeding programs to develop new pecan cultivars that will better meet consumer preferences and expectations, and therefore will be accepted by the processing industry and growers.

Influence of Cultivar on Nutritional Composition and Nutraceutical Potential of Pecan Growing in Uruguay

Composition and antioxidant properties of sixteen pecan [Carya illinoinensis (Wangenh) K. Koch] cultivars grown simultaneously in a single experimental orchard in Uruguay were evaluated to characterize their nutritional properties and nutraceutical potential. The percentage of oil, moisture, ash, minerals, and proteins were determined and also the fatty acid profile. Total phenolic compounds [18–41 mg gallic acid equivalents (GAEs)/g], condensed tannin [2–12 mg catechin equivalents (CEs)/g], and tocopherols (110–163 μg/g) contents were estimated in nut kernels. Total phenolic compounds (32–117 mg GAE/g), condensed tannins (130–357 mg CE/g), and total anthocyanins (1–3 mg 3-glucoside cyanidin/g) were also determined for pecan shells. The antioxidant activity in shells [57.15–578.88 μmol Trolox equivalents (TEs)/g] was 5 times higher compared with the kernels (23.15–156.60 μmol TEs/g) measured with hydrophilic ORAC. Bioactive compounds concentrations present statistically significant genetic variability between cultivars studied (p < 0.05). The presence of phenolic compounds was related with high-antioxidant capacity in kernels and shells, and a strong correlation between content of total phenolic compounds and condensed tannins in pecan shells was found. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) show association between cultivars and the observed variables. The nutritional profile in the different cultivars showed the trends described in other countries, but this work shows some significant differences that could be attributed to the specific edaphoclimatic conditions of cultivation in Uruguay.

A Comparison of Lipid Contents in Different Types of Peanut Cultivars Using UPLC-Q-TOF-MS-Based Lipidomic Study

Peanuts are a rich dietary source of lipids, which are essential for human health. In this study, the lipid contents of 13 peanut cultivars were analyzed using UPLC-Q-TOF-MS and GC–MS. The OXITEST reactor was used to test their lipid oxidation stabilities. A total of 27 subclasses, 229 individual lipids were detected. The combined analysis of lipid and oxidation stability showed that lipid unsaturation was inversely correlated with oxidation stability. Moreover, lipid profiles differed significantly among the different peanut cultivars. A total of 11 lipid molecules (TG 18:2/18:2/18:2, TG 24:0/18:2/18:3, TG 20:5/14:1/18:2, TG 18:2/14:1/18:2, PE 17:0/18:2, BisMePA 18:2/18:2, PG 38:5, PMe 18:1/18:1, PC 18:1/18:1, MGDG 18:1/18:1, TG 10:0/10:1/18:1) might be employed as possible indicators to identify high oleic acid (OA) and non-high OA peanut cultivars, based on the PLS-DA result of lipid molecules with a VIP value greater than 2. This comprehensive analysis will help in the rational selection and application of peanut cultivars.

Effect of pecan nuts and extra-virgin olive oil on glycemic profile and nontraditional anthropometric indexes in patients with coronary artery disease: a randomized clinical trial

BACKGROUND/OBJECTIVES

The influence of cardioprotective foods on nontraditional indexes related to dysglycemia and body fat distribution is unknown in individuals with coronary artery disease (CAD). This study aimed to evaluate the effect of a healthy diet supplemented with pecan nuts or extra-virgin olive oil on glycemic profile and adipose tissue dysfunction assessed by anthropometric indexes in patients with stable CAD.

SUBJECTS/METHODS

In a randomized, pragmatic, parallel clinical trial lasting 12 weeks, 204 individuals were allocated to three interventions: a healthy diet (control group [CG], n = 67), a healthy diet plus 30 g/day of pecan nuts (pecan nut group [PNG], n = 68), or a healthy diet plus 30 mL/day of extra-virgin olive oil (olive oil group [OOG], n = 69). Triglyceride-glucose (TyG) index (primary outcome) and other markers of glycemic profile were evaluated, and nontraditional anthropometric indexes as well. Diet quality was assessed according to the Alternate Healthy Eating Index (mAHEI).

RESULTS

After adjustment for baseline values, use of antidiabetic drugs and insulin, there were no differences in both glycemic and anthropometric profiles according to groups at the end of the study. PNG improved the quality of the diet in comparison to other groups (final mAHEI scores: CG: 19 ± 7.5; PNG: 26 ± 8; OOG: 18.9 ± 6; P < 0.001).

CONCLUSIONS

There was no difference regarding glycemic and anthropometric parameters according to interventions in patients with stable CAD. However, adding pecan nuts to a healthy diet may improve its quality. Further studies must be conducted considering dietary interventions on secondary cardiovascular prevention setting.

CLINICAL TRIALS IDENTIFIER NUMBER

NCT02202265. First Posted: July 2014; Last Update: September 2020.

Effects of extra virgin olive oil and pecans on plasma fatty acids in patients with stable coronary artery disease

OBJECTIVE

The aim of this study was to determine the effects of a healthy diet supplemented with extra virgin olive oil or pecans on plasma fatty acids (PFAs) in patients with stable coronary artery disease (CAD).

METHODS

Patients 40 to 80 y of age were randomized to one of three dietary interventions (allocation ratio 1: 1: 1): healthy diet based on guidelines (control group [CG]), healthy diet supplemented with 30 g/d of pecans (PNG), or a healthy diet supplemented with 30 mL/d of extra virgin olive oil (OOG). PFAs were identified at baseline and at the end of follow-up (12 wk), and correlations between dietary fatty acids intake, PFAs, and clinical biomarkers of the lipid profile were also assessed before and after the interventions.

RESULTS

Among 149 participants included in the analysis (43 CG; 51 PNG; and 55 OOG), correlations were observed between food intake, PFAs, and lipid profile before and after interventions independent of statins used, but all were considered weak. At the end of the study, the OOG showed increased concentrations of oleic fatty acid independently of the type of statin in use (1.49%; 95% confidence interval, 0.08-2.89; P = 0.029); however, there were no significant differences between the groups regarding the final mean values of oleic fatty acid or in the other PFAs.

CONCLUSIONS

In patients with stable CAD, there were no significant differences in PFAs after 12 wk according to dietary interventions evaluated.