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. https://doi.org/10.1111/1541-4337.12906
Cashew Apples in Ghana: Stakeholders' Knowledge, Perception, and Utilization.
Cashew (Anacardium occidentale), a crop projecting Ghana internationally beside cocoa, is usually cultivated for its nut, for both local and international markets. The cashew apple is underutilized in many African countries. This study is aimed at determining the knowledge, perception, and utilization of cashew apples in Ghana among stakeholders in the cashew value chain. Results from the study showed that the cashew industry consisted of farmers (89.1%), nut buyers (6.8%), extension officers (3.5%), and processors (0.6%) with uneven distribution of males (66.2%) and females (33.8%). Cashew apple utilization was low (<10%), though 84.37% had in-depth knowledge on the health benefits and value-added products made from the apples. Cashew apple is mainly utilized as fresh fruits or juice, with minor uses as an ingredient in food preparation, animal feed formulation, and production of mushroom, weedicide, ethanol, and manure. The cashew apple processors identified high cost of processing equipment, perishability of apples, lack of capital, market, technical know-how, and government support as challenges. Based on these findings, education of the stakeholders on value addition or processing of the apples at household and industrial levels and provision of stimulus packages to private processors are recommended to maximize cashew apple utilization in Ghana. https://doi.org/10.1155/2022/2749234
Agronomical and Physiological Behavior of Spanish Hazelnut Selection "Negret-N9" Grafted on Non-suckering Rootstocks
"Negret" is the most widely planted hazelnut cultivar in Northeastern Spain, where it is highly appreciated by the local kernel marked for its favorable nut traits. Its main disadvantages are the high suckers emission, causing large maintenance costs every year, and its medium-to-low vigor and susceptibility to iron chlorosis. In 2000, a trial to select new vigorous and non-suckering rootstocks for hazelnut was established at IRTA Mas Bové (Spain). The "Negret N-9" selection was grafted onto four clonal rootstocks ("Dundee" and "Newberg" two selections of open-pollinated Corylus colurna seedlings, the low suckering cultivar "Tonda Bianca" and the local selection "IRTA MB-69") and compared to the self-rooted "Negret N-9" as a control. The trial was designed as a randomized complete block with 10 replications and one tree per plot (10 trees per treatment). Plant vigor, suckers emission, yield, and nut and kernel traits have been evaluated over 10 years (2003-2012). During the 2006 to 2010 growing seasons, the qualitative traits of kernels, such as kernel skin color, oil content, and fatty acid profiles, were added to the characterization. Physiological data, such as steam water potential, stomatal conductance, and leaf chlorophyll content, were also evaluated during the 2015 growing season. The results showed that clonal rootstocks had a strong influence on vigor and yield of "Negret N-9." The "Dundee," "Newberg," and "IRTA MB-69" rootstocks showed the highest vegetative growth and the lower suckers emission. The yield was highest in trees grafted on "Dundee" rootstock. In terms of the qualitative traits of kernel which are important to the hazelnut industry, rootstocks increased the oil stability and induced a brown light color in the kernel pellicle versus the brown dark color observed in nuts collected from self-rooted "Negret N-9." The fatty acids profile was also influenced by the grafting combination. Finally, physiological traits indicated a higher overall performances for "Dundee" rootstock, which was generally found to be the best rootstock for "Negret N-9" in the experimental environment. https://doi.org/10.3389/fpls.2021.813902
Metabolite Profiling and Transcriptome Analyses Provide Insight Into Phenolic and Flavonoid Biosynthesis in the Nutshell of Macadamia Ternifolia
Macadamia ternifolia is a dynamic oil-producing nut crop in the world. However, the nutshell is frequently considered as a low-quality material. Further, its metabolic profile is still uncharacterized. In order to explore the industrial significance of the nutshell, this study performed metabolic and transcriptomic analyses at various developmental stages of the nutshell. The qualitative and quantitative metabolic data analysis identified 596 metabolic substances including several species of phenolic acids, flavonoids, lipids, organic acids, amino acids and derivatives, nucleotides and derivatives, alkaloids, lignans, coumarins, terpenoids, tannins, and others. However, phenolic acids and flavonoids were predominant, and their abundance levels were significantly altered across various developmental stages of the nutshell. Comparative transcriptome analysis revealed that the expression patterns of phenolic acid and flavonoid pathway related genes were significantly changed during the nutshell growth. In particular, the expression of phenylalanine ammonia-lyase, C4H, 4CL, CHS, CHI, F3H, and FLS had dynamic differences at the various developmental stages of the nutshell. Our integrative metabolomic and transcriptomic analyses identified the key metabolic substances and their abundance levels. We further discussed the regulatory mechanism of phenolic and flavonoid biosynthesis in the nutshell of M. ternifolia. Our results provide new insights into the biological profiles of the nutshell of M. ternifolia and help to elucidate the molecular mechanisms of phenolic and flavonoid biosynthesis in the nutshell of M. ternifolia. https://doi.org/10.3389/fgene.2021.809986
Evaluation of fungal hazards associated with dried fig processing
The processing of dried figs in the industry involves a number of stages that present a significant risk of filamentous fungal infection of the fruit and subsequent mycotoxin contamination, due to the changes in temperature and water activity (aw) to which dried figs are exposed. In this study, the environmental conditions and the physicochemical parameters of dried figs at different processing stages were evaluated in 3 different industries, and were associated with fungal counts and the presence of toxigenic molds and their mycotoxins. For this, dried figs at 5 relevant stages of industrial processing (curing, sizing, blanching, storage, and final product) in 3 industries located in Extremadura (Spain) were sampled. Changes in moisture content and aw of dried figs during processing were observed and they influenced the mycological quality of figs. Among the fungal genera, Aspergillus spp. predominated in most stages except blanching, where Penicillium spp. prevailed. About 10% of the dried fig samples were contaminated with aflatoxins (AFs) and 6% with ochratoxin A (OTA). Based on findings, longer drying times are necessary after blanching to reduce aw and to avoid the development of toxigenic molds. In addition, all stages covering industry processing, final storage, and retailing of dried figs are advisable to be conducted at refrigeration conditions and controlled relative humidity to avoid mycotoxin production. The enumeration of AFs- and OTA- producing molds by real-time PCR seems to be a good indicator for integration into prevention strategies to control filamentous fungal hazards and subsequent mycotoxin synthesis during the processing of dried figs. https://doi.org/10.1016/j.ijfoodmicro.2022.109541
Determination of Mycotoxins in Dried Fruits Using LC-MS/MS-A Sample Homogeneity, Troubleshooting and Confirmation of Identity Study.
To monitor co-exposure to toxic mycotoxins in dried fruits, it is advantageous to simultaneously determine multiple mycotoxins using a single extraction and liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis. In this study, we applied a stable isotope dilution and LC-MS/MS method to multi-mycotoxin analysis in dried fruits, selecting raisins, plums, figs, and cranberries for matrix extension. Samples were prepared using cryogenic grinding, followed by the fortification of carbon-13 (13C) uniformly labeled internal standards for twelve mycotoxins, and extraction using 50% acetonitrile. Homogeneity of prepared samples, defined as particle size Dv90 < 850 µm for the tested matrices, was characterized using a laser diffraction particle size analyzer, and reached using cryogenic grinding procedures. The majority of recoveries in the four matrices for aflatoxins and ochratoxin A spiked at 1-100 ng/g; fumonisins, T-2 toxin, HT-2 toxin, and zearalenone spiked at 10-1000 ng/g, ranged from 80 to 120% with relative standard deviations (RSDs) of <20%. Deoxynivalenol was not detected at 10 and 100 ng/g in plums, and additional troubleshooting procedures using liquid-liquid extraction (LLE), solid phase extraction (SPE), and elution gradient were evaluated to improve the detectability of the mycotoxin. Furthermore, we confirmed the identity of detected mycotoxins, ochratoxin A and deoxynivalenol, in incurred samples using enhanced product ion scans and spectral library matching. https://doi.org/10.3390/foods11060894
Marketing Orders Update: April 2022
USA: Decreased Assessment Rate for Pecans Grown in 15 States
Effective from May 16, 2022.
More information
USA: Increased Assessment Rate for Pistachios
This rule implements a recommendation from the Administrative Committee for pistachios to increase the assessment rate established for the 2021-22 and subsequent production years. It regulates the handling of pistachios grown in California, Arizona, and New Mexico.
Effective from May 16, 2022.
More information
Labeling Update: April 2022
EU: Scientific Advice on Nutrient Profiling
Dried fruits and nuts are among the food groups analyzed. In food group/category‐based nutrient profiling models, the panel concludes that total fat could replace energy in most food groups owing to its high energy density, while the energy density of food groups with low or no fat content may be well accounted for by the inclusion of (added/free) sugars. Some nutrients may be included in nutrient profiling models for reasons other than their public health importance, e.g., as a proxy for other nutrients of public health importance, or to allow for better discrimination of foods within the same food category.
More information
Pesticides Update: April 2022
EFSA Publishes Annual Report on Pesticide Residue Levels in Food
The rate of MRL exceedances (5.1%) increased compared with 2019 (3.9%) and 2018 (4.5%). It remained high for specific crops such as processed Brazil nuts, which are not covered in the EU multi-annual control program (MACP).
More information
EFSA Publishes National Reports on Pesticide Residue Analysis
More information
EU: New MRLs for Certain Products
| Flutolanil | Mg/kg |
| Peanuts/groundnuts | 0.02 |
| Proquinazid | Mg/kg |
| Cranberries | 1.5 |
Food Safety Update: April 2022
Chile: Phytosanitary Import Requirements for Peanuts
Some of the measures established are:
- Shipments must be covered by an official phytosanitary certificate issued by the country of origin, along with the additional declaration indicated in point 1.1 of the document attached to this notification;
- Moreover, some alternative additional declarations are described in point 1.2 of the notified draft. Phytosanitary treatments are established with their respective fumigation schedules;
- The seal must arrive in Chile intact, otherwise, it will be cause for rejection, a situation that may be analyzed by SAG, at the request of the exporting NPPO. Shipments must be free of plant remains;
- Shipments must be free of soil; this is understood to mean clods greater than or equal to 3 mm in diameter, a requirement that must be verified by the exporting NPPO prior to issuing the phytosanitary certificate;
- The wood used for packaging, pallets and packing materials must comply with the quarantine regulations for importation;
- Each shipment shall be inspected by SAG, at the point of entry, in order to ensure that the physical and documentary import requirements have been met.
EU: Call for Data on Contaminants
Deadline to submit data is October 1, 2022.
More information
EU: Answers Requested on Import Tolerances
The letter concerns EU MRLs for Alpha-cypermethrin, buprofezin, chlorothalonil, chlorpyrifos, chlorpyrifos-methyl, diflubenzuron, ethoxysulfuron, glufosinate, imazalil, ioxynil, ipodrione, mancozeb, molinate, picoxystrobin and tepraloxydim.
More information
South Korea: Country Report
Peanuts, pine nuts and walnuts are among the food items known to be food allergens and must be indicated on the label, even if they are added at minimal levels as part of a mix.
Regarding heavy metals in agricultural products:
| Target Foods | Lead (mg/kg) | Cadmium (mg/kg) |
| Peanuts and tree nuts | Not more than 0.1 | Not more than 0.3 |
In-shell walnuts from California are the only product subject to a pre-clearance program. When in-shell walnuts from California are imported, Korea’s Animal and Plant Quarantine Agency (APQA) may conduct a document or visual inspection but does not perform laboratory testing.
More information