Influence of roasting conditions on health-related compounds in different nuts

Biomass partitioning and ionomics of Macadamia with high manganese and low phosphorus concentrations

Knowledge of the ionome of plant organs helps us understand a plant's nutritional status. However, the ionome of Macadamia (Proteaceae), which is an important nut-producing tree, remains unknown. We aimed to characterise the allocation of biomass and nutrient-partitioning patterns in three macadamia genotypes. We excavated 15 productive trees (three cultivars at 21years of age; two cultivars at 16years of age) in an orchard. Biomass, nutrient concentrations, and contents of roots, stems, branches, and leaves were analysed. Dry weight of roots, stems, branches and leaves accounted for 14-20%, 19-30%, 36-52%, and 12-18% of total plant weight, respectively. No significant difference was found in the total biomass among the cultivars at the same age. Compared with most crop plants, macadamia had low phosphorus (P) concentrations in all organs (<1gkg-1 ), and low leaf zinc (Zn) concentration (8mgkg-1 ). In contrast, macadamia accumulated large amounts of manganese (Mn), with a 20-fold higher leaf Mn concentration than what is considered sufficient for crop plants. Leaves exhibited the highest nutrient concentrations, except for iron and Zn, which exhibited the highest concentrations in roots. The organ-specific ionomics of Macadamia is characterised by low P and high Mn concentrations, associated with adaptation to P-impoverished habitats.

Assessing the Impact of Roasting Temperatures on Biochemical and Sensory Quality of Macadamia Nuts (Macadamia integrifolia)

Depending on the temperature regime used during roasting, the biochemical and sensory characteristics of macadamia nuts can change. 'A4' and 'Beaumont' were used as model cultivars to examine how roasting temperatures affected the chemical and sensory quality of macadamia nuts. Using a hot air oven dryer, macadamia kernels were roasted at 50, 75, 100, 125, and 150 °C for 15 min. The quantity of phenols, flavonoids, and antioxidants in kernels roasted at 50, 75, and 100 °C was significant (p < 0.001); however, these kernels also had high levels of moisture content, oxidation-sensitive unsaturated fatty acids (UFAs), and peroxide value (PV), and poor sensory quality. Low moisture content, flavonoids, phenols, antioxidants, fatty acid (FA) compositions, high PV, and poor sensory quality-i.e., excessive browning, an exceptionally crunchy texture, and a bitter flavor-were all characteristics of kernels roasted at 150 °C. With a perfect crispy texture, a rich brown color, and a strong nutty flavor, kernels roasted at 125 °C had lower PV; higher oxidation-resistant UFA compositions; considerable concentrations of flavonoids, phenols, and antioxidants; and good sensory quality. Therefore, 'A4' and 'Beaumont' kernels could be roasted at 125 °C for use in the industry to improve kernel quality and palatability.

Phytoextracts for Human Health from Raw and Roasted Hazelnuts and from Hazelnut Skin and Oil: A Narrative Review

The objectives of this narrative review are as follows: an evaluation of the bromatological composition of hazelnuts and a comparison of the nutritional properties of raw versus roasted hazelnuts, taking into account potential differences among varieties from different production territories such as Turkey, Italy, Chile, and New Zealand; an evaluation of nutrients contained in hazelnut skin; and an evaluation of nutrients contained in hazelnut oil. This review incorporates 27 scientific articles that measured and reported the concentrations of macro- and micro-nutrients in hazelnuts. These hazelnuts were subjected to different processing methods, originated from various geographical areas, or belonged to different varieties. Our results showed that the different varieties and territories where the hazelnuts were cultivated influence their bromatological composition, and we found that different processing steps can largely influence the concentration of specific nutrients. The removal of the skin, which contains a very high concentration of compounds with antioxidant action, is particularly critical. We should give greater attention to the skin, considering it not as a waste product, but as an important part of the hazelnut due to its nutritional properties of primary relevance in the Mediterranean diet. We provide a detailed assessment of the nutritional properties of the hazelnut kernel, skin, and oil, evaluating nutrient compositions and possible modifications (increases or reductions) that occur during the roasting process or that depend on the production territory and origin.

Composition of Nuts and Their Potential Health Benefits-An Overview

The possibility that nut intake may defend human health is an interesting point of view and has been investigated worldwide. Consequently, nuts are commonly promoted as healthy. In recent decades, the number of investigations proposing a correlation between nut consumption and a decrease in the risk of key chronic diseases has continued to increase. Nuts are a source of intake of fiber, and dietary fiber is associated with a reduced occurrence of obesity and cardiovascular diseases. Nuts likewise provide minerals and vitamins to the diet and supply phytochemicals that function as antioxidant, anti-inflammatory, and phytoestrogens agents and other protective mechanisms. Therefore, the main goal of this overview is to summarize current information and to describe the utmost new investigation concerning the health benefits of certain nuts.

Investigation on the contents of heat-induced hazards in commercial nuts

The purpose was to investigate the contents of heat-induced hazards by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in 44 commercial nuts. Results showed that content ranges of Acrylamide (AA), 5-hydroxymethylfurfural (5-HMF), N^ε-carboxymethyl-lysine (CML), N^ε-carboxyethyl-lysine (CEL), 3-Deoxyglucosone (3-DG), Glyoxal (GO), and Methylglyoxal (MGO) were ND-123.57 µg/kg, 0.57-213.42 mg/kg, 3.18-18.67 mg/kg, 3.98-57.85 mg/kg, 1.5-133.86 mg/kg, 0.45-1.59 mg/kg and 0.29-13.84 mg/kg, respectively. Sunflower seeds contained more heat-induced hazards followed by pistachios, cashews, almonds, walnuts and hazelnuts. The content of 5-HMF was positively correlated with the content of 3-DG. CML exhibited positive correlation with content of GO while no correlation between CEL and MGO. Higher levels of 3-DG and 5-HMF were observed in nuts produced with sugar and honey. Deep processing had a stronger promoting effect on CML and CEL formation. These data could provide a crucial guide for consumers to select nut products which might reduce heat-induced hazards intake.

Plant-based milk: unravel the changes of the antioxidant index during processing and storage - a review

As a nutrient rich emulsion extracted from plant materials, plant-based milk (PBM) has been the latest trend and hot topic in the food industry due to the growing awareness of consumers toward plant-based products in managing the environmental (carbon footprint and land utility), ethical (animal well-fare) and societal (health-conscious) issues. There have been extensive studies and reviews done to discuss the distinct perspective of PBM including its production, health effects and market acceptance. However, not much has been emphasized on the valuable antioxidants present in PBM which is one of the attributes making them stand apart from dairy milk. The amounts of antioxidants in PBM are important. They offered tremendous health benefits in maintaining optimum health and reducing the risk of various health disorders. Therefore, enhancing the extraction of antioxidants and preserving their activity during production and storage is important. However, there is a lack of a comprehensive review of how these antioxidants changes in response to different processing steps involved in PBM production. Presumably, antioxidants in PBM could be potentially lost due to thermal degradation, oxidation or leaching into processing water. Hence, this paper aims to fill the gaps by addressing an extensive review of how different production steps (germination, roasting, soaking, blanching, grinding and filtration, and microbial inactivation) affect the antioxidant content in PBM. In addition, the effect of different microbial inactivation treatments (thermal or non-thermal processing) on the alteration of antioxidant in PBM was also highlighted. This paper can provide useful insight for the industry that aims in selecting suitable processing steps to produce PBM products that carry with them a health declaration.

Effect of drying on the physical and chemical properties of palm kernel oil

BACKGROUND

Palm kernel is the edible seed of the oil palm fruit obtained during the palm oil milling process. For efficient processing and storage, the moisture content of palm kernel must be reduced to an optimal level by drying. This study aimed to see how drying influenced the physical structure and physicochemical properties of palm kernel and oil. Before and after drying, the free fatty acid (FFA), color, fatty acid composition, Fourier transform infrared, thermal properties and structure of palm kernel were investigated.

RESULTS

Results show that drying significantly (P < 0.05) reduced FFA and color of palm kernel oil. Drying also significantly affected (P < 0.05) composition of some fatty acids in palm kernel oil such as capric acid, lauric acid, myristic acid, palmitic acid and oleic acid. However, drying did not affect palm kernel and palm kernel oil functional groups and thermal properties. After drying, structural damage of palm kernel was observed.

CONCLUSION

Based on these findings, the quality of kernel oil may be maintained after drying, and it can even be improved based on lower FFA content. © 2022 Society of Chemical Industry.

Optimization of formulation and process conditions of chestnut-based functional beverage using response surface methodology

Response surface methodology was used to optimize the chestnut beverage production under the effect of the independent variables including dilution rate (x ₁ ), dilution temperature (x ₂ ), pasteurization time (x ₃ ) and pasteurization temperature (x ₄ ). The experiments were based on a central composite design with linear and quadratic models employed to study the combined effects of four independent variables. The responses were selected with functional properties such as antioxidative attributes and total phenolic content. The optimal conditions (x ₁ , x ₂ , x ₃ and x ₄ ) determined for development of chestnut based functional beverage were a dilution rate of 25.19 g/100 mL, a dilution temperature of 37.562 °C, a pasteurization time of 24.996 min. and a pasteurization temperature of 84.433 °C. After comparing the predicted and experimental results, the multi-response surface methodology was more stable with a good correlation for a functional chestnut beverage.

Development of Food Group Tree-Based Analysis and Its Association with Non-Alcoholic Fatty Liver Disease (NAFLD) and Co-Morbidities in a South Indian Population: A Large Case-Control Study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a global problem growing in parallel to the epidemics of obesity and diabetes, with South Asians being particularly susceptible. Nutrition and behaviour are important modifiers of the disease; however, studies to date have only described dietary patterns and nutrients associated with susceptibility to NAFLD.

METHODS

This cross-sectional case-control study included 993 NAFLD patients and 973 healthy controls from Trivandrum (India). Dietary data was collected using a locally validated food frequency questionnaire. A tree-based classification categorised 2165 ingredients into three levels (food groups, sub-types, and cooking methods) and intakes were associated with clinical outcomes.

RESULTS

NAFLD patients had significantly higher consumption of refined rice, animal fat, red meat, refined sugar, and fried foods, and had lower consumption of vegetables, pulses, nuts, seeds, and milk compared to controls. The consumption of red meat, animal fat, nuts, and refined rice was positively associated with NAFLD diagnosis and the presence of fibrosis, whereas consumption of leafy vegetables, fruits, and dried pulses was negatively associated. Fried food consumption was positively associated with NAFLD, whilst boiled food consumption had a negative association. Increased consumption of animal fats was associated with diabetes, hypertension, and cardiovascular outcomes among those with NAFLD, whereas consumption of wholegrain rice was negatively associated with these clinical-related outcomes.

CONCLUSIONS

The tree-based approach provides the first comprehensive method of classifying food intakes to enable the identification of specific dietary factors associated with NAFLD and related clinical outcomes. This could inform culturally sensitive dietary guidelines to reduce risk of NAFLD development and/or its progression.

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.

Microwave-Assisted Extraction Coupled to HPLC-UV Combined with Chemometrics for the Determination of Bioactive Compounds in Pistachio Nuts and the Guarantee of Quality and Authenticity

Two novel microwave-assisted extraction (MAE) methods were developed for the isolation of phenols and tocopherols from pistachio nuts. The extracts were analyzed by reversed-phase high-pressure liquid chromatography coupled with a UV detector (RP-HPLC-UV). In total, eighteen pistachio samples, originating from Greece and Turkey, were analyzed and thirteen phenolic compounds, as well as α-tocopherol, (β + γ)-tocopherol, and δ-tocopherol, were identified. The analytical methods were validated and presented good linearity (r² > 0.990) and a high recovery rate over the range of 82.4 to 95.3% for phenols, and 93.1 to 96.4% for tocopherols. Repeatablility was calculated over the range 1.8–5.8%RSD for intra-day experiments, and reproducibility over the range 3.2–9.4%RSD for inter-day experiments, respectively. Principal component analysis (PCA) was employed to analyze the differences between the concentrations of the bioactive compounds with respect to geographical origin, while agglomerative hierarchical clustering (AHC) was used to cluster the samples based on their similarity and according to the geographical origin.

Postharvest processing of tree nuts: Current status and future prospects-A comprehensive review

Tree nuts are important economic crops and are consumed as healthy snacks worldwide. In recent years, the increasing needs for more efficient and effective postharvest processing technologies have been driven by the growing production, higher quality standards, stricter food safety requirements, development of new harvesting methods, and demand to achieve energy saving and carbon neutralization. Among all, the technologies related to drying, disinfection, and disinfestation and downstream processes, such as blanching, kernel peeling, and roasting, are the most important processes influencing the quality and safety of the products. These processes make up the largest contribution to the energy consumptions and environmental impacts stemming from tree nut production. Although many studies have been conducted to improve the processing efficiency and sustainability, and preserve the product quality and safety, information from these studies is fragmented and a centralized review highlighting the important technology advancements of postharvest processing of tree nuts would benefit the industry. In this comprehensive review, almonds, walnuts, and pistachios are selected as the representative crops of tree nuts. Current statuses, recent advances, and ongoing challenges in the scientific research as well as in the industrial processing practices of these tree nuts are summarized. Some new perspectives and applications of tree nut processing waste and by-products (such as the hulls and shells) are also discussed. In addition, future trends and research needs are highlighted. The material presented here will help both stakeholders and scientists to better understand postharvest tree nut processing and provide technological recommendations to improve the efficiency and sustainability, product quality and safety, and competitiveness of the industry.

Raw walnut kernel: A natural source for dietary proteases and bioactive proteins

Walnut kernels are health-promoting nuts, which are mainly attributed to polyunsaturated fatty acids, phenolics, and phytosterols. However, the information concerning benefits of walnut proteins are limited. In this study, endopeptidases, aminopeptidases, carboxypeptidases, superoxide dismutases, catalases, and phospholipases with respective relative abundance of 2.730, 1.728, 0.477, 3.148, 0.743, and 0.173‰ were identified by liquid chromatography tandem mass spectrometry. These endogenous proteases exhibited activity in a broad pH range of 2-6.5, and optimal at pH 4.5 and 50 °C. Aspartic endopeptidases were predominant endopeptidases, followed by cysteine ones. There were two types of aspartic endopeptidases, one (not inhibited by pepstatin A) exerted activity at pH 2-3 and the other (inhibited by pepstatin A) optimal at pH 4.5. Carboxypeptidases were optimal at pH 4.5, and aminopeptidases exerted activity at pH near 6.5. These endogenous proteases assisted the digestion of walnut proteins, and soaking, especially peeling, greatly improved the in vitro digestibility.

Effect of Food Processing on Antioxidant Potential, Availability, and Bioavailability

Antioxidants are understood to play a key role in disease prevention; because of this, research and interest in these compounds are ever increasing. Antioxidative phytochemicals from natural sources are preferred, as some negative implications have been associated with synthetic antioxidants. Beans, nuts, seeds, fruits, and vegetables, to name a few, are important sources of phytochemicals, which have purported health benefits. The aforementioned plant sources are reportedly rich in bioactive compounds, most of which undergo some form of processing (boiling, steaming, soaking) prior to consumption. This article briefly reviews selected plants (beans, nuts, seeds, fruits, and vegetables) and the effects of processing on the antioxidant potential, availability, and bioavailability of phytochemicals, with research from our laboratory and other studies determining the health benefits of and processing effects on bioactive compounds.

Characterization of iron walnut in different regions of China based on phytochemical composition

Little is known about the phytochemical composition of iron walnuts. Differences in the geographical origin of iron walnuts associated with economic benefits should also be examined. In this study, the phytochemical composition (fatty acids, Vitamin E, total polyphenols and flavonoids, amino acids, and minerals) of iron walnuts in China was investigated. The results showed that there were significant differences (p < 0.05) in the phytochemical composition of iron walnut oils and flours from different regions. Positive (r > 0.5, p < 0.05) and negative (r < - 0.5, p < 0.05) correlations were found between amino acids/minerals and amino acids/oleic acid, with the highest correlation coefficient (r = 0.742, p < 0.05) between Cu and tyrosine. In addition, based on the 12 phytochemical fingerprints selected by random forest, a geographical-origin identification model for iron walnuts was established, with a corresponding correct classification rate of 96.6%. The top three phytochemical fingerprints for the geographical-origin identification of iron walnut were microelements, macroelements, and antioxidant composition, with contribution rates of 61.7%, 18.1%, and 9.9%, respectively.

A comprehensive study of raw and roasted macadamia nuts: Lipid profile, physicochemical, nutritional, and sensory properties

Macadamia nuts have high nutritional value and positive health attributes. Changes to the composition and availability of these compounds during roasting contribute to product quality. In this study, changes to the chemical composition of lipids (fatty acids, triglycerides, and free fatty acids) and other phytochemicals were analyzed, and a sensory evaluation was carried out of two major varieties of macadamia nuts planted in China, after roasting. Only small changes in fatty acid (FA) content and a slight decrease in total triglycerides (TAGs) were observed after roasting. The free fatty acid (FFA) content and the peroxide value were increased by roasting. The total available polyphenol content increased by 25.6% and the oxidative stability index of kernels increased by 21.6%. The sensory scores for taste and aroma were doubled by roasting. Overall, the sensory, nutritional quality, and oxidative stability of roasted macadamia nuts were greatly improved, compared with raw nuts.

Variability of Chemical Profile in Almonds (Prunus dulcis) of Different Cultivars and Origins

Almonds show a great variability in their chemical composition. This variability is a result of the existence of a diverse range of almond cultivars, the self-incompatibility of most almond cultivars, and the heterogeneous harvesting conditions found around the different locations where almons are grown. In the last years, the discrimination among almond cultivars has been the focal point of some research studies to avoid fraud in protected geographical indications in almond products and also for selecting the best cultivars for a specific food application or the most interesting ones from a nutritional point of view. In this work, a revision of the recent research works related to the chemical characterization and classification of almond cultivars from different geographical origins has been carried out. The content of macronutrients, tocopherols, phytosterols, polyphenols, minerals, amino acids, and volatile compounds together with DNA fingerprint have been reported as possible cultivar and origin markers. The analysis of the results showed that no individual almond compound could be considered a universal biomarker to find differences among different almond cultivars. Hence, an adequate selection of variables or the employment of metabolomics and the application of multivariate statistical techniques is necessary when classification studies are carried out to obtain valuable results. Meanwhile, DNA fingerprinting is the perfect tool for compared cultivars based on their genetic origin.

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.

Effects of Different Processing Treatments on Almond (Prunus dulcis) Bioactive Compounds, Antioxidant Activities, Fatty Acids, and Sensorial Characteristics

Almond is one of the most commonly consumed nuts worldwide, with health benefits associated with availability of bioactive compounds and fatty acids. Almond is often eaten raw or after some processing steps. However, the latter can positively or negatively influence chemical and sensorial attributes of almonds. This work was carried out to assess the effects of two processing treatments, namely; roasting and blanching on (i) contents of bioactive compounds, (ii) contents of fatty acids (3) antioxidant activities (4), sensorial characteristics of four neglected Portuguese almond cultivars (Casanova, Molar, Pegarinhos and Refêgo) and two foreign cultivars (Ferragnès and Glorieta). Results showed that in general, levels of bioactive compounds and antioxidant activities increased with roasting and decreased with blanching. Fatty acid profiles of raw kernels of all cultivars were generally identical although Refêgo exhibited a high content of α-linolenic acid. Following roasting and blanching, content of polyunsaturated fatty acids increased while saturated fatty acids, monounsaturated fatty acids and several health lipid indices decreased. Roasting positively affected perception of skin color and sweetness of Ferragnès and Glorieta as well as skin roughness of Molar and Pegarinhos. Blanching on the other hand led to positive changes in textural properties of Refêgo and Pegarinhos. This study reveals the nutritive benefits of consuming neglected almond cultivars in Portugal, and the novel data reported here could be of interest to growers, processing companies and consumers.

Thermal inactivation of Salmonella, Shiga toxin-producing Escherichia coli, Listeria monocytogenes, and a surrogate (Pediococcus acidilactici) on raisins, apricot halves, and macadamia nuts using vacuum-steam pasteurization

Salmonella, Shiga toxin-producing Escherichia coli (STEC), and Listeria monocytogenes have been isolated from low water activity foods (LWAF), where they may survive for extended periods. The ready-to-eat nature of many LWAF, such as dried fruits and nuts, warrants effective post-harvest thermal treatment for the reduction of pathogens such as low-temperature, saturated steam, also known as vacuum-assisted steam pasteurization. The objective of this study was to determine reductions of Salmonella, STEC, L. monocytogenes, and a possible surrogate (Pediococcus acidilactici) on dried apricot halves, whole macadamia nuts, and raisins after treatment with vacuum-assisted steam at three temperatures (62 °C, 72 °C, or 82 °C) and multiple time intervals. Bacterial inactivation was variable between commodities, with higher temperatures and longer times necessary to achieve comparable reductions of pathogens on apricot halves and macadamia nuts compared to raisins. Reductions of the tested pathogens were comparable; therefore, one species was not more resistant than the others. Pathogens were reduced by 5-log CFU/g on apricot halves after 20 min at 72 °C and after 5 min at 82 °C. Longer treatment times were necessary to achieve reductions of each pathogen on macadamia nuts. Pathogens were reduced by nearly 5 log CFU/g on macadamia nuts after 38 min at 72 °C (4.6-6.5 log CFU/g) and after 12 min at 82 °C (4.9-5.7 log CFU/g). Reductions of pathogens on raisins were achieved at lower temperatures than necessary for the other foods. A 5-log reduction for each of the pathogens (CFU/g) on raisins occurred after 20 min at 62 °C and after 5 min at 72 °C. Overall, the reductions of the pathogens exceeded those of P. acidilactici on both the dried fruits and macadamia nuts. Statistically significant differences, indicating greater confidence as a conservative surrogate, were observed at lower treatment temperatures. Inactivation kinetics were modeled for each pathogen on each food type and temperature. Bacterial survival was best described by the Weibull model for raisins and macadamia nuts, while the Gompertz model best described reductions on apricot halves according to Akaike information criterion (AIC) and root-mean-square error (RMSE) evaluations. Water activity and moisture content were increased due to the treatments, which could be addressed through implementation of drying steps. Thermal inactivation kinetic models and 5-log reduction parameters can help food processors design and evaluate similar vacuum-assisted steam interventions to comply with FSMA regulations and preventive control plans. However, results or model predictions should not be extrapolated to assume the safety of other types of foods.

Nutrient Composition of Different Hazelnut Cultivars Grown in Germany

Hazelnuts are rarely cultivated in Germany, although they are a valuable source for macro- and micronutrients and can thus contribute to a healthy diet. Near the present, 15 varieties were cultivated in Thuringia, Germany, as a pilot study for further research. The aim of our study was to evaluate the micro- and macronutrient composition of representative, randomly mixed samples of the 15 different hazelnut cultivars. Protein, fat, and fiber contents were determined using established methods. Fatty acids, tocopherols, minerals, trace elements, and ultra-trace elements were analyzed using gas chromatography, high-performance liquid chromatography, and inductively coupled plasma triple quadrupole mass-spectrometry, respectively. We found that the different hazelnut varieties contained valuable amounts of fat, protein, dietary fiber, minerals, trace elements, and α-tocopherol, however, in different quantities. The variations in nutrient composition were independent of growth conditions, which were identical for all hazelnut varieties. Therefore, each hazelnut cultivar has its specific nutrient profile.

Influence of microwave treatment on quality parameters of snacks food. Impact issuees

The following publication presents results of the research on a new, innovative, mild technology of food processing with microwaves technology in order to develop novel food in the form of “on the go” healthy snacks. Different aspects of microwave treatment technologies within the context of physical model of electromagnetic field interaction with a food product, marketing and energy aspects were considered. Furthermore, comparison of sensory quality of conventionally and microwave treated nuts was shown, which is a key feature of nuts, seeds and dried fruits for most consumers. A comparative LCA analysis of convectional and microwave roasting was performed as well.

The Association between Nuts Intake and Non-Alcoholic Fatty Liver Disease (NAFLD) Risk: a Case-Control Study

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease. Nuts are nutrient- and calorie-dense foods with several health-promoting compounds. In this case-control study, we investigated the association between nut intake and NAFLD risk. Hundred ninety-six subjects with NAFLD and eight hundred three controls were recruited. The participants' dietary intakes were assessed by a valid and reliable semi-quantitative food frequency questionnaire (FFQ). Participants were categorized according to deciles of daily nuts intake. Multivariable logistic regression models were used with NAFLD as the dependent and deciles of daily nuts intake as an independent variables. Range of age was 18 to 75 years. Forty three percent of participants were male. Range of nuts intake was between 0 to 90.90 g/day. In model 3, after adjusting for potential confounding variables including, age, sex, BMI, alcohol consumption, smoking, diabetes and physical activity, the relation between daily nuts intake and risk of NAFLD was positive and significant in the deciles 9 and 10 compared to the lowest decile (odds ratio [OR], 3.22; 95% confidence interval [CI], 1.04-7.49; p = 0.039 and OR, 3.03; 95% CI, 1.03-8.90; p = 0.046, respectively). However, in the final model after additional adjusting for energy intake, no significant association was found. According to the findings, there is not any significant relationship between nuts intake and NAFLD risk; while higher intake of nuts is related to the higher risk of NAFLD mediated by energy intake.

Effects of different roasting methods on formation of acrylamide in pistachio

Drying and roasting are conventional processes in the nut industry. However, roasting as an important procedure in nuts manufacturing may cause some physicochemical changes in nuts. Acrylamide is one of these chemical compounds that is formed due to the roasting process. Acrylamide is known as a neurotoxicant, carcinogen, and reproductive toxicant. In this study, raw and salted pistachios were roasted under three conditions including hot-air, infrared (IR), and microwave methods. Then, 80 pistachio kernels were analyzed by ultra-high-performance liquid chromatography. The results showed that all samples contained different ranges of acrylamide between 57 ± 0.86 and 851 ± 2.8 μg/kg. Besides, raw pistachios and sun-dried pistachios also contained acrylamide, with the amount of 57 ± 0.86 and 93 ± 1.07 μg/kg, respectively. The highest acrylamide amount was found in raw pistachio (unsalted) roasted by IR method, while lower acrylamide amount observed in the microwave method. The amount of acrylamide in salted and roasted pistachios was less than just roasted pistachios under the same conditions. Finally, in all the treatments, increasing temperature, time, voltage, and power lead to an increase in acrylamide levels. The results showed that acrylamide in the roasted pistachios may cause health problems. This study presents a novel investigation in the effects of roasting conditions (temperature, power, voltage, and time) on acrylamide content in pistachios.

Bioactives and health benefits of nuts and dried fruits

Nuts and dried fruits have been part of the human diet since prehistoric times. They are nutrient-rich foods and constitute an excellent means to deliver health-promoting bioactive compounds. As such, they serve as important healthful snack items, besides being part of many traditional and new recipes of gastronomy worldwide. Frequent consumption of nuts and/or dried fruits is highly recommended to obtain the full benefit of the nutrients, bioactives, and antioxidants that they contain, together with their desirable flavour. The macronutrients, micronutrients, and other health-promoting bioactive compounds contained in nuts and dried fruits may synergistically contribute to modulate the risk of cardiometabolic and other non-communicable diseases through various mechanisms. Experimental research, prospective studies, and human clinical trials have reported beneficial effects of nut consumption on various health outcomes. The benefits of dried fruits, however, have been less explored. This review summarizes recent findings on bioactive constituents, health claims, and health benefits of nuts and dried fruits and also discusses their great potential as healthy foods to benefit a number of diseases afflicting human beings.

Walnut paste: oxidative stability and effect of grape skin extract addition

Walnut paste, obtained by roasting and grinding of kernels, was characterized and supplemented with encapsulated grape skin extract aiming to evaluate its potential effect on oxidative stability and/or antioxidant capacity. Based on the oxidation induction period in screening trials 5000 ppm (w/w) extract addition was selected as effective in inhibiting oxidation processes. Walnut paste with and without 5000 ppm grape skin extract were maintained for 15 days at 60 °C, simulating 2 year storage at 20 °C, based on an estimated activation energy of 80,327 kJ/mol for walnut lipid oxidation. Monitoring of data from peroxides, conjugated dienes and trienes, total phenolics, ABTS, ORAC, FRAP, and tocopherols values showed the deterioration of walnut paste started at the end of the observed period, even remaining below the threshold of unacceptability. Moreover, 5000 ppm extract addition did not prove to enhance oxidative stability nor antioxidant properties of the walnut paste. In the future, specific parameters of oxidation kinetics and antioxidant activity in the advanced phase of storage could be investigated.

Association between nut intake and non-alcoholic fatty liver disease risk: a retrospective case-control study in a sample of Chinese Han adults

OBJECTIVES

Nut consumption has been associated with a lower risk of type 2 diabetes, metabolic syndrome and insulin resistance. However, its effect on the risk of non-alcoholic fatty liver disease (NAFLD) is unknown. Therefore, we investigated the relationship between nut consumption and NAFLD risk.

SETTING AND PARTICIPANTS

We conducted a retrospective case-control study including 534 patients diagnosed with NAFLD and 534 controls matched by sex and age (±5 years) from the Affiliated Nanping First Hospital of Fujian Medical University in China.

MAIN OUTCOME MEASURES

Information on dietary intake was collected using a semiquantitative food frequency questionnaire and nut consumption was calculated. Nut consumption was categorised using quartiles based on the distribution of daily nut intake of the controls. Binary logistic regression models were used to estimate ORs and the 95% CIs for the association between nut consumption and NAFLD risk.

RESULTS

After adjusting for potential confounding variables, nut consumption was not associated with NAFLD risk in the overall sample. When the fully adjusted model was stratified by sex, a significant inverse association was found between high nut consumption and NAFLD only among the men in the highest quartile (OR=0.43; 95% CI 0.26 to 0.71; P_{trend =} 0.01). The inverse association of nut consumption with NAFLD risk in men remained significant after controlling for other known or suspected risk factors for NAFLD.

CONCLUSIONS

Diets with a higher intake of nuts may be associated with a decreased risk of NAFLD, particularly in men.

In Vitro Digested Nut Oils Attenuate the Lipopolysaccharide-Induced Inflammatory Response in Macrophages

Nut consumption is known for its health benefits, in particular in inflammatory diseases. A possible mechanism for these effects could be their beneficial fatty acid composition. Nuts mainly contain mono- and polyunsaturated fatty acids, which have anti-inflammatory properties. However, studies investigating the effects of nut extracts on inflammatory processes on the molecular level are rare. We therefore prepared oily nut extracts after in vitro digestion and saponification of the fat-soluble constituents. Besides chromatographic analysis, cell culture experiments were performed using murine macrophages (RAW264.7) to study the capacity of different nut extracts (hazelnut, almond, walnut, macadamia, and pistachio) to modulate inflammatory processes. Oleic acid was the main fatty acid in hazelnut, almond, macadamia, and pistachio extracts. Both oily nut extracts and pure oleic acid significantly reduced the LPS-induced expression of iNos, Cox2, Tnfα, Il1β, and Il6 mRNAs. iNos protein expression was down-regulated followed by reduced nitric oxide formation. Thus, nut extracts at concentrations achievable in the digestive tract inhibit the expression and formation of inflammatory mediators in macrophages. Hence, a beneficial contribution of nut consumption to inflammatory diseases can be assumed. We are convinced that these results provide new insights on the molecular mechanisms involved in the health-beneficial effects of nuts.

Effect of Roasting and Storage on the Formation of Maillard Reaction and Sugar Degradation Products in Hazelnuts ( Corylus avellana L.)

This study investigated the effect of roasting (150 °C for 30 min) and storage (12 months at 4 °C, 25 °C, and 25 °C in vacuum package), conditions of which are generally applied in the industry and markets, on the formation of Maillard reaction and sugar degradation products, namely dicarbonyl compounds, 5-hydroxymethylfurfural, N-ε-fructosyllysine, and N-ε-carboxymethyllysine in Tombul and Levant hazelnuts. Roasting increased all dicarbonyl compounds significantly ( p < 0.05). The concentration of methylglyoxal was the highest while 1-deoxyglucosone was the lowest in roasted hazelnuts. 5-Hydroxymethylfurfural and N-ε-carboxymethyllysine also increased significantly ( p < 0.05) with roasting while furosine decreased. Roasting changed the progress of the Maillard reaction from the early stage to the advanced stage. On the other hand, there were no significant changes ( p > 0.05) in the concentration of Maillard reaction and sugar degradation products independent of the storage conditions or time and hazelnut variety, except for glyoxal, diacetyl, and 1-deoxyglucosone. Therefore, neither 5-hydroxymethylfurfural nor furosine is suggested as a storage marker of the Maillard reaction and sugar degradation.

Impact of different roasting conditions on chemical composition, sensory quality and physicochemical properties of waxy-barley products

Roasting improves sensory properties and differentially modulates health-related compounds of barley products.

Process Optimization for Improved Phenolic Compounds Recovery from Walnut (Juglans regia L.) Septum: Phytochemical Profile and Biological Activities

Plant by-products can be valuable sources of polyphenol bioactive compounds. Walnut (Juglans regia L.) is a very important tree nut rich in biologically active molecules, but its septum was scarcely researched. Experimental data indicated a hypoglycemic effect of septum extracts, with almost no details about its phytochemical composition. The main objectives of this study were: (1) to obtain walnut septum (WS) extracts with high content in bioactive compounds and antioxidant activity based on an original experimental design; (2) characterization of the phytochemical profile of the WS extracts using HPLC-MS/MS; (3) evaluation of the biological potential of the richest polyphenolic WS extract. The variables of the experimental design were: extraction method (maceration and Ultra-Turrax extraction), temperature, solvent (acetone and ethanol), and percentage of water in the solvent. The first quantifiable responses were: total phenolic content, total flavonoid content, condensed tannins, and ABTS antioxidant capacity. The phytochemical profile of lyophilized extracts obtained by Ultra-Turrax extraction (UTE), the most efficient method, was further determined by HPLC-MS/MS analysis of individual polyphenolic and phytosterols compounds. It is the first study to assay the detailed composition of WS in hydrophilic and lipophilic compounds. The biological potential of the richest polyphenolic WS extract was also evaluated by FRAP and DPPH antioxidant capacity and the inhibition of tyrosinase, an enzyme involved in the browning in fruits and vegetables, skin wrinkles and aging. Conclusion: The phytochemical profile of the analyzed extracts proves that WS can be a valuable source of biologically active compounds (polyphenols) for food and/or pharmaceutical industry and warrant the continuation of current research in further evaluating its bioactive potential.

Optimizing Physiochemical and Sensory Properties of Infrared-Hot Air Roasted Sunflower Kernels Using Response Surface Methodology

Roasting sunflower kernels is a key process in production of nuts. In this study, the effect of roasting conditions, including hot air temperature (120–160°C), infrared (IR) power (400–600 W) and roasting time (3–10 min) on energy and specific energy consumption, color parameters (L∗, a∗, b∗, ΔE, BI, SI, WI, and h°), texture, moisture content, chemical properties (pH and total phenolic contents, peroxide value (PV), and sensory properties of sunflower kernel were investigated. In addition, the best models for the responses were obtained, and the proper roasting conditions were determined using response surface methodology (RSM). A quadratic model was proposed for color change (L∗, ΔE, SI, and WI), moisture and total phenol contents, linear relation for a∗, b∗, h°, and 2FI for BI, texture, PV, and pH. Roasting at 425.7 W IR power and 124.3°C for 3.7 min was found to be convenient or proper roasting conditions.

The relationship between nut intake and risk of colorectal cancer: a case control study

BACKGROUND

Nut consumption is known to reduce the risk of obesity, diabetes mellitus, and cardiovascular disease. However, in previous studies, portion sizes and categories of nut consumption have varied, and few studies have assessed the association between colorectal cancer risk and nut consumption. In this study, we investigated the relationship between nut consumption and colorectal cancer risk.

METHODS

A case-control study was conducted among 923 colorectal cancer patients and 1846 controls recruited from the National Cancer Center in Korea. Information on dietary intake was collected using a semi-quantitative food frequency questionnaire with 106 items, including peanuts, pine nuts, and almonds (as 1 food item). Nut consumption was categorized as none, < 1 serving per week, 1-3 servings per week, and ≥3 servings per week. A binary logistic regression model was used to estimate odds ratios (OR) and their 95% confidence intervals (CI) for the association between nut consumption and colorectal cancer risk, and a polytomous logistic regression model was used for sub-site analyses.

RESULTS

High nut consumption was strongly associated with reduced risk of colorectal cancer among women (adjusted ORs: 0.30, 95%CI: 0.15-0.60 for the ≥3 servings per week group vs. none). A similar inverse association was observed for men (adjusted ORs: 0.28, 95% CI: 0.17-0.47). In sub-site analyses, adjusted ORs (95% CIs) comparing the ≥3 servings per week group vs none were 0.25 (0.09-0.70) for proximal colon cancer, 0.39 (0.19-0.80) for distal colon cancer, and 0.23 (0.12-0.46) for rectal cancer among men. An inverse association was also found among women for distal colon cancer (OR: 0.13, 95% CI: 0.04-0.48) and rectal cancer (OR: 0.40, 95% CI: 0.17-0.95).

CONCLUSIONS

We found a statistically significant association between high frequency of nut consumption and reduced risk of colorectal cancer. This association was observed for all sub-sites of the colon and rectum among both men and women, with the exception of proximal colon cancer for women.

Effect of roasting conditions on the composition and antioxidant properties of defatted walnut flour

BACKGROUND

Walnut oil extraction by pressure systems produces a press cake as a by-product, with many of the beneficial walnut properties. The objective of this work was to evaluate the composition and antioxidant properties of walnut flours submitted to different roasting protocols (50, 100 and 150 °C during 30, 60 and 120 min).

RESULTS

All walnut flours had about 42% protein and a significant amount of dietary fibre (17%), not being affected by the roasting process. Nonetheless, the fat content increased around 50% in walnuts flours subjected to longer and higher roasting temperatures (150 °C). The lipid fraction showed a good nutritional quality with a high vitamin E content (mainly γ-tocopherol) and fatty acid profile rich in linoleic and linolenic acids. The high phenolic content also provides great antioxidant capacity to the flours.

CONCLUSION

Mild roasting of walnuts did not affect the quality of the flours that could be used as a functional ingredient in the food industry. © 2017 Society of Chemical Industry.

Chemopreventive Potential of Raw and Roasted Pistachios Regarding Colon Carcinogenesis

Pistachios are rich in health-promoting bioactive compounds such as B vitamins, γ-tocopherol, polyphenols and dietary fiber, which could contribute to the reduction of colon cancer risk in terms of chemoprevention (Fischer, S.; Glei, M. Health-Potential of Nuts. Ernaehrungs Umsch. Int. 2013, 60, 206-215.). Since pistachios are often consumed roasted, the present study aims at investigating the influence of different roasting conditions (RC) on potential chemopreventive effects of pistachios in colon adenoma cells such as growth and apoptosis, genotoxic- and anti-genotoxic effects and modulation of gene expression of detoxifying enzymes (CAT, SOD2, GPx1, and GSTP1). Fermentation supernatants (FS) were obtained from raw and roasted (RC1 = 141 °C/25 min, RC2 = 160 °C/15 min and RC3 = 185 °C/21 min) pistachios after in vitro fermentation. FS of pistachios significantly reduced LT97 cell growth in a time- and dose-dependent manner. Compared to the blank control, pistachio FS (2.5%) led to a significant average reduction of H₂O₂-induced DNA damage (1.5-fold). Levels of CAT mRNA were significantly increased (1.3-fold, on average for 5% FS). Pistachio FS (5%) significantly increased the number of early apoptotic cells (up to 2.1-fold) and levels of caspase-3 activities (up to 6.9-fold). The present results confirm a chemopreventive potential of pistachios, which is mediated by growth inhibition, induction of apoptosis and anti-genotoxic effects, as well as induction of CAT. These effects remain mostly unaffected by roasting.

Current nut recommendation practices differ between health professionals in New Zealand

OBJECTIVE

Despite evidence linking regular nut consumption with reduced chronic disease risk, population-level intakes remain low. Research suggests nut-promoting advice from doctors facilitates regular nut consumption. However, there is no information on current nut recommendation practices of health professionals. The aim of the present study was to examine the advice provided by health professionals regarding nut consumption.

DESIGN

In this cross-sectional study, participants were invited to complete a survey including questions about their nut recommendation practices.

SETTING

New Zealand (NZ).

SUBJECTS

The NZ Electoral Roll was used to identify dietitians, general practitioners and practice nurses.

RESULTS

In total 318 dietitians, 292 general practitioners and 149 practice nurses responded. Dietitians were more likely (82·7 %) to recommend patients increase consumption of nuts than general practitioners (55·5 %) and practice nurses (63·1 %; both P<0·001). The most popular nuts recommended were almonds, Brazil nuts and walnuts, with most health professionals recommending raw nuts. The most common recommendation for frequency of consumption by dietitians and practice nurses was to eat nuts every day, while general practitioners most frequently recommended 2-4 times weekly, although not statistically significantly different between professions. Dietitians recommended a significantly greater amount of nuts (median 30 g/d) than both general practitioners and practice nurses (20 g/d; both P<0·001).

CONCLUSIONS

Dietitians were most likely to recommend consumption of nuts in accordance with current guidelines, but there are opportunities to improve the adoption of nut consumption recommendations for all professions. This may be a viable strategy for increasing population-level nut intakes to reduce chronic disease.