Effects of different roasting temperatures on the flavor characteristics of shelled macadamia kernels: Analysis based on HS-GC-IMS and HS-SPME-GC–MS
This study aimed to evaluate the effect of roasting temperature on the flavor characteristics of shelled macadamia kernels (SMKs) employing quantitative descriptive sensory analysis, color analysis, and two volatile compound profiling techniques, namely headspace-solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC–MS) and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). Sensory and color analyses showed that roasting at 140 °C yielded a desirable roasted macadamia product, exhibiting a rich balsam flavor, creamy aroma, and uniform, harmonious faint yellow color. HS-SPME-GC–MS and HS-GC-IMS identified 107 volatile organic compounds (VOCs). Aldehydes, pyrazines, and furans increased with increasing roasting temperature, and these compounds were key contributors to the nutty aroma. Lipid oxidation dominated flavor formation during low-temperature roasting, while Strecker degradation prevailed at high temperatures. Among the VOCs, 23 with relative odor activity values (ROAV) of ≥1 contributed significantly to the overall aroma of roasted SMK. Furthermore, HS-SPME-GC–MS and HS-GC-IMS identified 10 and 16 key VOCs, respectively, including 2-methylpyrazine, 2,5-dimethylpyrazine, 2-ethylpyrazine, nonanal, and propanal. Interestingly, ethanol content showed a significant negative correlation (p < 0.05) with “bitter,” and “burnt”, as well as with a*, b*, and c, whereas most pyrazine compounds exhibited positive correlations with these sensory attributes (p < 0.05). Altogether, the findings of this study present roasting as an effective approach for enhancing macadamia nut aroma and provide valuable insights for flavor control in nut products.
https://doi.org/10.1016/j.foodres.2026.118878
Dynamics of Polyphenolic Compounds During Wet Processing of Peanuts
The study analyzed changes in phenolic compounds and the total polyphenol content during peanut sauce cooking, comparing samples prepared with peanuts with and without kernel coating. The peanut sauce formulation consisted of 3.3% w/v peanut powder mixed with water, which was boiled for 2 h at around 100°C. Methanol extracts were used to assess the polyphenol content. Identification and quantification of phenolic compounds were performed using high-performance liquid chromatography (HPLC). Nine polyphenols were identified, including several phenolic acids (4-hydroxybenzoic acid, vanillic acid, p-coumaric acid, and trans-ferulic acid), flavonoids (daidzein, quercetin, genistein, and kaempferol), and one stilbene (resveratrol). The concentrations of 4-hydroxybenzoic acid, p-coumaric acid, resveratrol, daidzein, and genistein in the noncoated peanuts significantly increased from 0 to 60 min (from 70 to 120 μg/g, 20 to 30 μg/g, 5 to 10 μg/g, 30 to 60 μg/g, and 30 to 50 μg/g, respectively), followed by degradation at extended cooking up to 120 min. In conclusion, the removal of the coating resulted in a more pronounced maxima and degradation of these compounds during the cooking process. The results can be understood by applying a consecutive model describing the release of bound polyphenols and the degradation of free polyphenols during the cooking process.
https://doi.org/10.1155/jfpp/8525758
Postharvest gas treatments for almonds: Efficacy, lipid oxidation and practical implications for quality preservation
Postharvest management of high-oil nuts such as almonds must reconcile disinfestation with preservation of lipid quality. Rigorous, life-stage–resolved comparisons that quantify both insect control and almond quality remain scarce. An integrated benchmark was conducted on shelled almonds infested with Tribolium castaneum (Herbst, 1797; Coleoptera: Tenebrionidae) and Oryzaephilus surinamensis (Linnaeus, 1758; Coleoptera: Silvanidae) (larvae and adults), evaluating three gaseous treatments: ozone (O3; 500 ppm, 6 h), phosphine (PH3; 1 g m−3, 7 d), and an ECO2Fume CO2-based treatment (50 g m−3, 3 d). Across five independent replicates, biological endpoints (mortality, fecundity, nutritional indices, energy conversion index, and almond weight loss) were quantified alongside a chemical quality panel (proteins, Thiobarbituric acid reactive substances, free fatty acids, proximate composition, minerals, total phenolics, oil). PH3 achieved the highest and most consistent mortality (≈89–99%) and markedly suppressed feeding and progeny while inducing only minor immediate changes in lipid-oxidation indices. The CO2-based treatment delivered comparable control (≈86–94%) with modest chemical shifts and pronounced reductions in consumption and weight loss. By contrast, O3 produced only moderate insecticidal effects (≈55–66% mortality) but caused clear oxidative deterioration (ΔPV = +2.31; ΔTBARS = +0.90; ΔFFA = +0.145; total phenolics ≈ −15.9%). Multivariate synthesis of Principal component analysis (PCA) and Canonical variate analysis (CVA) indicated that a primary axis dominated by oxidation markers explained ∼88% of treatment variance (Can1; P < 0.001), whereas a secondary axis captured insect-response variation (∼11%; Can2; P < 0.001). Findings delineate a practical trade-off between pest suppression and lipid-quality preservation and support prioritization of PH3 or CO2-based approaches over ozone for high-oil commodities unless oxidative impacts can be mitigated.
https://doi.org/10.1016/j.jspr.2026.102969
Compositional Characteristics, Texture, Shelf‐Life and Sensory Quality of Sweet Walnut Pastes
Walnut pastes represent a promising functional food product due to the nutritional value of walnuts (Juglans regia L.). However, little is known about the impact of formulation and processing on their stability during storage. This study aimed to assess the effect of formulation and processing variables conditions for walnut paste production and to evaluate the physicochemical, textural, microbiological, and sensory stability of the product over time. A complete factorial design was used to develop pastes with varying walnut content (70%, 80%, and 90%) using both roasted (120°C for 20 min) and unroasted walnuts. Ingredients such as sugar, soy lecithin, salt, ascorbic acid, potassium sorbate, and antioxidants were proportionally adjusted. All formulations were stored at 4°C for 180 days. The oxidative stability index ranged from 25.39 to 16.84 h, with higher stability observed in samples containing synthetic antioxidants. Peroxide values and conjugated diene levels remained lowest in formulations containing butylated hydroxytoluene. Acidity values stayed below 0.50 mg KOH/g oil, indicating negligible lipid hydrolysis. Roasting significantly improved spreadability and smoothness, as confirmed by instrumental and sensory analysis. No microbial growth of Escherichia coli, Salmonella spp., Clostridium perfringens, or Penicillium aurantiogriseum was detected in any sample throughout storage. These findings evidence that appropriate formulation and roasting can enhance both the oxidative stability and sensory quality of walnut pastes, demonstrating their potential as a stable and health spreadable product.
https://doi.org/10.1002/aocs.70046
Physically crosslinked polyphenol-chitosan edible coating for the application of walnut kernels during roasting
This study developed an edible chitosan-based coating incorporating the main polyphenols from walnut kernel seed coats (gallic acid, ferulic acid, and ellagic acid) to enhance the oxidative stability and sensory quality of fresh walnut kernels during roasting. SEM and AFM analysis revealed that gallic acid-loaded chitosan films exhibited a uniform yet rough morphology, while zeta potential measurements (36-41 mV) confirmed improved film stability. The gallic acid-loaded film demonstrated superior wettability (contact angle: 21.45°) and low water vapor permeability (2.87 × 10-3 g/(mm∙h∙kPa)), ensuring strong adhesion. FTIR and UV-Vis analyses confirmed hydrogen-bonded crosslinking between polyphenols and chitosan. Thermal stability increased, with DSC and TGA peaks at 181.97 °C and 343 °C for the gallic acid-loaded film. Coated kernels exhibited significantly lower oxidation, with peroxide and acid values (0.04 g/100 g, 0.5 mg/g) outperforming uncoated samples. These findings suggested that gallic acid-loaded chitosan coatings effectively improve walnut kernel quality during roasting.
https://doi.org/10.1016/j.foodchem.2026.147846
Cashew nut protein concentrate as a potential ingredient for the emerging alternative protein industry
This study evaluated protein concentrates obtained from cashew nuts defatted by three different strategies: mechanical pressing (PE), hexane extraction (HE), and aqueous extraction (AE). Protein concentrates (PC-A, PC-P, and PC-H, from AE, PE, and HE, respectively) were produced through alkaline extraction followed by isoelectric precipitation. PCs were characterized for protein functionality, nutritional and chemical profiling. Protein contents were 59.34 % (PC-P), 85.45 % (PC-H), and 69.02 % (PC-A). All samples had high in vitro digestibility, above 90 %, and a balanced amino acid profile. Maximum protein solubility was achieved for all PCs at pH 8 and above (>50 %). PC-A showed superior oil-holding capacity and emulsifying capacity, similar gelation properties and reduced water holding capacity when compared to the other PCs. Overall, AE emerges as an ecofriendly alternative for producing high-quality cashew protein concentrate with less environmental impact than HE, while hexane extraction remains the most efficient method for oil removal.
https://doi.org/10.1016/j.foodchem.2025.146855
Recent Advances in the Mechanisms of Quality Degradation and Control Technologies for Peanut Butter: A Literature Review
As the quality of life continues to improve globally, there is an increasing demand for nutritious and high-quality food products. Peanut butter, a widely consumed and nutritionally valuable product, must meet stringent quality standards and exhibit excellent stability to satisfy consumer expectations and maintain its competitive position in the market. However, its high fat content, particularly unsaturated fatty acids, makes it highly susceptible to quality deterioration during storage. Key issues such as fat separation, lipid oxidation, and rancidity can significantly compromise its texture, flavor, and aroma, while also reducing its shelf life. Understanding the underlying mechanisms that drive these processes is essential for developing effective preservation strategies. This understanding not only aids food scientists and industry professionals in improving product quality but also enables health-conscious consumers to make informed decisions regarding the selection and storage of peanut butter. Recent research has focused on elucidating the mechanisms responsible for the quality deterioration of peanut butter, with particular attention to the intermolecular interactions among its key components. Current regulatory techniques aimed at improving peanut butter quality encompass raw material selection, advancements in processing technologies, and the incorporation of food additives. Among these innovations, plant protein nanoparticles have garnered significant attention as a promising class of green emulsifiers. These nanoparticles have demonstrated potential for stabilizing peanut butter emulsions, thereby mitigating fat separation and oxidation while aligning with the growing demand for environmentally friendly food production. Despite these advances, challenges remain in optimizing the stability and emulsifying efficiency of plant protein nanoparticles to ensure the long-term quality and stability of peanut butter. Future research should focus on improving the structural properties and functional performance of these nanoparticles to enhance their practical application as emulsifiers. Such efforts could provide valuable theoretical and practical insights into the development of stable, high-quality peanut butter, ultimately advancing the field of food science and technology.
https://doi.org/10.3390/foods14010105
Almond Shell Utilization in Next-Generation Biocomposite Packaging: A Review
Background: The profound use of polyethylene-derived packaging materials has generated significant environmental problems with its non-degradability. The necessity of sustainable substitutes has resulted in intensive research on bio-based packaging materials. Almond shells are the byproduct of almond production, either discarded or burned in the almond industry. Scope and approach: Almond shells have potential food packaging applications that focus on waste reduction and sustainability. This review examines the prospect of almond shells, a cheap agro-industrial waste, as a desirable building block for next-generation biocomposite packaging material. Transitioning to almond shell-based food packaging can emphasize biodegradability, recyclability, and use of renewable resources. Key findings and conclusions: Almond shells are abundant in lignocellulosic content and improve the mechanical properties, thermal stability, and barrier behavior of biodegradable polymer matrices, hence providing a potential reinforcement of biopolymers like polylactic acid (PLA) and starch composites. Although potentially valuable, processing inefficiency, cost, and regulatory issues deter wide-ranging applicability. Future breakthroughs in nanotechnology, intelligent packaging, and advanced manufacturing processes, including 3D printing for customized and functional biocomposite packaging, can further enhance almond shell-based biocomposites' functionality and commercial potential. There must be a strategic transition towards bio-based packaging, accompanied by policy encouragement and industry cooperation, to mitigate plastic pollution and create a more sustainable packaging sector.
https://doi.org/10.1016/j.tifs.2025.105258
Quality Assessment of Prune Jam with Different Concentration Methods Based on Physicochemical Properties, GC-IMS, and Intelligent Sensory Analysis
This study systematically investigated the impacts of four concentration methods-vacuum freezing concentration (VFC), microwave vacuum concentration (MVC), atmospheric thermal concentration (ATC), and vacuum thermal concentration (VTC)-on the quality and volatile compounds of prune jam. Advanced analytical techniques, including electronic tongue, electronic nose, gas chromatography-ion mobility spectrometry (GC-IMS), and multivariate statistical methods (principal component analysis, partial least squares discriminant analysis), were employed to evaluate physicochemical properties and flavor profiles. Results showed that non-thermal methods (particularly VFC) significantly outperformed thermal methods (ATC/VTC) in nutrient preservation. For instance, VFC retained 91.4% of ascorbic acid and limited dietary fiber loss to 4.55%, while ATC caused up to 60.1% ascorbic acid degradation and 51.75% dietary fiber loss. In terms of color stability, VFC induced a 1.04-fold increase in browning index (BI) and a 2.54-fold increase in total color difference (ΔE), significantly lower than ATC's 1.6-fold BI increase and 7.26-fold ΔE rise. GC-IMS identified 42 volatile compounds, categorized into aldehydes (17), alcohols (9), esters (7), etc. Multivariate analysis screened 15 key flavor compounds (VIP > 1, p < 0.05), such as ethyl acetate and methanol, revealing that non-thermal methods better preserved the characteristic sweet-sour flavor and reduced off-flavor formation. These findings highlight VFC's superiority in maintaining nutritional and sensory quality, providing scientific guidance for industrial jam production and flavor optimization in fruit processing.
https://doi.org/10.3390/foods14122084
Enrichment of Rice Flour with Almond Bagasse Powder: The Impact on the Physicochemical and Functional Properties of Gluten-Free Bread
Almond bagasse, a by-product of almond milk production, is rich in fibre, protein, polyunsaturated fatty acids, and bioactive compounds. Its incorporation into food products provides a sustainable approach to reducing food waste while improving nutritional quality. This study explored the impact of enriching rice flour with almond bagasse powders-either hot air-dried (HAD60) or lyophilised (LYO)-at substitution levels of 5%, 10%, 15%, 20%, 25%, and 30% (w/w), to assess effects on gluten-free bread quality. The resulting flour blends were analysed for their physicochemical, techno-functional, rheological, and antioxidant properties. Gluten-free breads were then prepared using these blends and evaluated fresh and after seven days of refrigerated storage. The addition of almond bagasse powders reduced moisture and water absorption capacities, while also darkening the bread colour, particularly in HAD60, due to browning from thermal drying. The LYO powder led to softer bread by disrupting the starch structure more than HAD60. All breads hardened after storage due to starch retrogradation. The incorporation of almond bagasse powder reduced the pasting behaviour-particularly at substitution levels of ≥ 25%-as well as the viscoelastic moduli of the flour blends, due to fibre competing for water and thereby limiting starch gelatinisation. Antioxidant capacity was significantly enhanced in HAD60 breads, particularly in the crust and at higher substitution levels, due to Maillard reactions. Furthermore, antioxidant degradation over time was less pronounced in formulations with higher substitution levels, with HAD60 proving more stable than LYO. Overall, almond bagasse powder improves the antioxidant profile and shelf-life of gluten-free bread, highlighting its value as a functional and sustainable ingredient.
https://doi.org/10.3390/foods14132382