Antimicrobial and antioxidant activity of phenolic extracts from walnut (Juglans regia L.) green husk by using pressure-driven membrane process.
In this study, antioxidant (DPPH and metal chelating), DNA cleavage, biofilm, and antimicrobial properties of extracted phenol from the walnut green husk (WGH) and its different concentrate and permeate samples were evaluated. For maximum phenolic compound extraction from the WGH first, the effects of solvent type (deionized water, methanol, n-hexane, acetone, and ethanol), solvent temperature (25-75 °C), and extraction time (0.5-24 h) were optimized. Then to concentrate phenolic compounds a pressure-driven membrane process was used with four different membrane types. The phenol contents of the concentrate samples were found to be microfiltration (MF) concentrate 4400 mg/L, ultrafiltration (UF) concentrate 4175 mg/L, nanofiltration (NF) concentrate 8155 mg/L, and reverse osmosis (RO) concentrate 8100 mg/L. LC-MSMS was used to determine the quantification of phenolic compounds in permeate and concentrate streams. In addition, all of the concentrate samples with high phenol content showed a high antioxidant activity as 100% with MF concentrate, UF concentrate, NF concentrated and RO concentrated. Likewise, concentrate samples were found to have very high antibiofilm activity as 82.86% for NF concentrate against S. aureus, 85.80% for NF concentrate against P. aureginosa, 80.95% for RO concentrate against S. aureus, and 83.61% for RO-concentrate against P. aureginosa. When the antimicrobial activity of the extracted phenol from WGH and its different concentrate and permeate samples were evaluated by micro dilution and disk diffusion methods, it was found that the ability of the concentrate samples to inhibit bacterial growth was much higher than permeate ones. In addition, extracted phenol from WGH and its different concentrate and permeate samples showed significant DNA nuclease activity. https://doi.org/10.1007/s13197-022-05588-w
Practice and Progress: Updates on Outbreaks, Advances in Research, and Processing Technologies for Low-moisture Food Safety.
Large, renowned outbreaks associated with low-moisture foods (LMFs) bring to light some of the potential, inherent risks that accompany foods with long shelf lives if pathogen contamination occurs. Subsequently, in 2013, Beuchat et al. (2013) noted the increased concern regarding these foods, specifically noting examples of persistence and resistance of pathogens in low-water activity foods (LWAFs), prevalence of pathogens in LWAF processing environments, and sources of and preventive measures for contamination of LWAFs. For the last decade, the body of knowledge related to LMF safety has exponentially expanded. This growing field and interest in LMF safety have led researchers to delve into survival and persistence studies, revealing that some foodborne pathogens can survive in LWAFs for months to years. Research has also uncovered many complications of working with foodborne pathogens in desiccated states, such as inoculation methods and molecular mechanisms that can impact pathogen survival and persistence. Moreover, outbreaks, recalls, and developments in LMF safety research have created a cascading feedback loop of pushing the field forward, which has also led to increased attention on how industry can improve LMF safety and raise safety standards. Scientists across academia, government agencies, and industry have partnered to develop and evaluate innovate thermal and nonthermal technologies to use on LMFs, which are described in the presented review. The objective of this review was to describe aspects of the extensive progress made by researchers and industry members in LMF safety, including lessons-learned about outbreaks and recalls, expansion of knowledge base about pathogens that contaminate LMFs, and mitigation strategies currently employed or in development to reduce food safety risks associated with LMFs. https://doi.org/10.1016/j.jfp.2022.11.010
Hot air-assisted radio frequency drying of apricots: Mathematical modeling study for process design.
Conventional hot air and solar energy processes have been used for apricot. These processes had adverse effects on the quality due to the longer process times, and this indicates the need for an innovative approach. Radio frequency (RF) processing has innovation potential for drying with its volumetric heating feature, but an optimal process should be designed for process efficiency in industrial-scale applications. Therefore, the objective of this study was to confirm the RF process for industrial-scale apricot drying. For this purpose, a mathematical model was developed to predict temperature and moisture content change of apricots during drying, and experimental validation study was carried out. For the RF drying process, pre-dried apricots (0.58-0.75 kg water/kg dry matter, db) by solar energy were used. The purpose was to start the RF process at a suitable moisture content level as this process was not feasible to apply directly due to the high initial moisture content of apricots (up to 4 kg water/kg dry matter, db). RF drying experiments were carried out in a 10 kW hot air-assisted (50-60°C) staggered through electrode system. Optimum electrode gap was 81 mm with 2500 V potential of the charged electrode. Final moisture content of the dried apricots was 0.25-0.33 kg water/kg dry matter (db). Following the model validation for temperature and moisture content change, industrial-scale apricot drying scenarios were demonstrated to confirm the RF process for feasibility and process design. PRACTICAL APPLICATION: A comprehensive mathematical model was developed for radio frequency (RF) drying of apricots. This model was experimentally validated with respect to the temperature and moisture content change. Various process design studies were carried out for an industrial-scale apricot drying process to confirm the process feasibility. With this background, the results of this study can be directly used in an industrial drying for an optimal process design and energy efficiency. https://doi.org/10.1111/1750-3841.16021
Fluoride Bio-Sorption Efficiency and Antimicrobial Potency of Macadamia Nut Shells.
This paper presents the potential application of macadamia nut shells (MNS) in the bio-sorption of fluoride and its antimicrobial potency against common pathogens encountered in surface water resources. The efficiency of MNS in the sorption of fluoride was determined using batch mode experiments, while the antimicrobial potency was investigated using the well disc diffusion assay method. The maximum fluoride sorption capacity of 1.26 mg/g was recorded at an initial fluoride concentration of 5 mg/L, adsorbent dosage of 0.5 g/100 mL, contact time of 120 min and initial pH of 6. The adsorption kinetics data were better described with a pseudo second order model, indicating the dominance of the chemisorption mechanisms. The Langmuir adsorption isotherm model described the isotherm data suggesting a monolayered adsorption. The thermodynamic parameters, ∆Gº and ∆Hº, confirmed that F- sorption by MNS is a spontaneous and endothermic process. The bio-sorbent was regenerated for seven continuous cycles when HCl was used as regenerating solution. The antimicrobial studies revealed that MNS has minimal activity towards Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae. The MNS showed potentials for application in bio-sorption of fluoride. However, the doping of MNS with metal ions is recommended to enhance its anti-microbial potency. https://doi.org/10.3390/ma15031065
Assembly and comparative analysis of the complete mitochondrial genome of three Macadamia species (M. integrifolia, M. ternifolia and M. tetraphylla).
Background: Macadamia is a true dicotyledonous plant that thrives in a mild, humid, low wind environment. It is cultivated and traded internationally due to its high-quality nuts thus, has significant development prospects and scientific research value. However, information on the genetic resources of Macadamia spp. remains scanty. Results: The mitochondria (mt) genomes of three economically important Macadamia species, Macadamia integrifolia, M. ternifolia and M. tetraphylla, were assembled through the Illumina sequencing platform. The results showed that each species has 71 genes, including 42 protein-coding genes, 26 tRNAs, and 3 rRNAs. Repeated sequence analysis, RNA editing site prediction, and analysis of genes migrating from chloroplast (cp) to mt were performed in the mt genomes of the three Macadamia species. Phylogenetic analysis based on the mt genome of the three Macadamia species and 35 other species was conducted to reveal the evolution and taxonomic status of Macadamia. Furthermore, the characteristics of the plant mt genome, including genome size and GC content, were studied through comparison with 36 other plant species. The final non-synonymous (Ka) and synonymous (Ks) substitution analysis showed that most of the protein-coding genes in the mt genome underwent negative selections, indicating their importance in the mt genome. Conclusion: The findings of this study provide a better understanding of the Macadamia genome and will inform future research on the genus. https://doi.org/10.1371/journal.pone.0263545
Hazelnut extract-loaded nanostructured lipid carriers and evaluation of their antioxidant properties.
Reactive oxygen species (ROS) are a common hallmark of many degenerative diseases, developing in all those cases where a failure of physiological antioxidant mechanisms occurs (in particular, antioxidant enzymes and the glutathione system), or in case of exposure to an extremely high level of oxidants. In this regard, antioxidant natural extracts are promising compounds as preventive or therapeutic agents against ROS-dependent degenerations. In this study, a deep investigation of hazelnut (Corylus avellana) extract has been performed in terms of mass spectroscopy, evaluation of phenolic content, and antioxidant capacity. Then, nanostructured lipid carriers (NLCs) have been exploited for encapsulation of the hazelnut extracts in order to achieve prolonged bioactivity, increased stability, and targeting through a sustainable delivery approach. The hazelnut extract-loaded NLCs (NE_NLCs) have been deeply characterized for their stability, production yield, and encapsulation efficiency. Moreover, NE_NLCs showed optimal cytocompatibility on human dermal fibroblast (HDF) cells, as well as excellent antioxidant activity, upon pro-oxidant stimulus on HDF cells. https://doi.org/10.3389/fbioe.2022.953867
Frequency of Alternaria genotypes resistant to SDHI fungicides in California pistachio orchards determined by real-time PCR.
Real-time PCR methods were developed to quantify the frequency of SDHC-H134R and SDHB-H277Y mutants associated with SDHI resistance in Alternaria populations from pistachio. The linearity of the standard curves demonstrated the applicability in the quantification of the assays. The accuracy and reliability of the qPCR protocols to determine the frequency of mutants in real samples were corroborated. Orchards visibly affected by Alternaria Late Blight were sampled. The frequency of mutants were determined using the qPCR assays, while the frequency of resistant phenotypes was determined using a single discriminatory dose. The statistical analysis showed that the frequencies of the mutation SDHC-H134R determined with the qPCR assay were highly correlated with those estimated with the conventional method. The survey also evidenced that resistance to boscalid is still widespread in California. Results also indicated the possible contribution of other mutations to SDHI resistance. Our results confirmed the prevalence of SDHC-H134R mutants and the occurrence of mutation SDHB-H277Y at low frequencies. The real-time PCR methods developed in this study were able to detect differences in the frequencies of resistant mutants caused by the use of chemical fungicides. Finally, the effects of two fungicide programs on the frequency of mutants resistant to SDHI and QoI fungicides were studied using qPCR assays. The experiments demonstrated that the use of AP and DMI fungicides in the same program reduced the frequency of these mutations in Alternaria populations. The qPCR methods developed and used in this study can be used to track resistance levels in the pistachio orchards on a large scale. https://doi.org/10.1094/PDIS-08-22-2013-RE
One-class model with two decision thresholds for the rapid detection of cashew nuts adulteration by other nuts.
A green screening method to determine cashew nut adulteration with Brazilian nut, pecan nut, macadamia nut and peanut was proposed. The method was based on the development of a one-class soft independent modelling of class analogy (SIMCA) model for non-adulterated cashew nuts using near-infrared (NIR) spectra obtained with portable equipment. Once the model is established, the assignment of unknown samples depends on the threshold established for the authentic class, which is a key aspect in any screening approach. The authors propose innovatively to define two thresholds: lower model distance limit and upper model distance limit. Samples with distances below the lower threshold are assigned as non-adulterated with a 100% probability; samples with distance values greater than the upper threshold are assigned as adulterated with a 100% probability; and samples with distances within these two thresholds will be considered uncertain and should be submitted to a confirmatory analysis. Thus, the possibility of error in the sample assignment significantly decreases. In the present study, when just one threshold was defined, values greater than 95% for the optimized threshold were obtained for both selectivity and specificity. When two class thresholds were defined, the percentage of samples with uncertain assignment changes according to the adulterant considered, highlighting the case of peanuts, in which 0% of uncertain samples was obtained. Considering all adulterants, the number of samples that were submitted to a confirmatory analysis was quite low, 5 of 224 adulterated samples and 3 of 56 non-adulterated samples. https://doi.org/10.1016/j.talanta.2022.123916
Prepared activated carbon from hazelnut shell where coated nanocomposite with Ag+ used for antibacterial and adsorption properties.
In this research, prepared activated carbon by H3PO4 from hazelnut shells was coated with silver ions for the preparation of nanoparticles which were mixed in two ratios (1:0.5 and 1:1) by using of chemical reduction method. The adsorption capacity of activated carbons has been proven by BET and iodine number. Then, the antimicrobial effect of nanoparticles on the Staphylococcus aureus and Escherichia coli was investigated; in addition to that, the characterization of hazelnut shell and silver-coated activated carbons was determined by Brunauer-Emmett-Teller (BET), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) methods. The optimum condition of activated carbon from hazelnut shells indicated that 66.01% carbon content within 36.22% efficiency, while BET surface area achieved as 1208 m2/g and its contained 0.6104 cm3 g-1 total pore volume. The microbial effect indicated that 105 CFU/mL of E. coli was completely inhibited in 30 min. Silver-coated activated carbon showed excellent bacteriostatic activity against E. coli and S. aureus. The results show that the composite has good prospects for applications in drinking water. E. coli of 104 CFU/mL in drinking water were destroyed within 25 min of contact with the filter made with AgAC. https://doi.org/10.1007/s11356-022-23004-w
First Report of Colletotrichum fructicola Causing anthracnose on macadamia in China.
Macadamia (Macadamia ternifolia Maiden and Betche) is an important commercial crop in the world and has the reputation of being the king of nuts (Liu et al. 2019). In August 2020, symptoms of anthracnose appeared on leaves of macadamia in Chongzuo, Guangxi Province, China, with an incidence of 15-20%. The disease developed from the edge of leaf. Initially, the disease symptoms on leaves were faded green spots, light yellow. After expanding and linking together, the leaves appeared brown or black irregular spots, and the edges of diseased leaves dried up and formed large necrosis, eventually leading to defoliation. A large number of orange-yellow spots (acervuli) developed on the diseased parts. Under high humidity conditions, the diseased part was grayish-brown or black, and a large number of yellowish-brown conidia were produced on the leaf surface (Fig.1 A-E). Ten symptomatic leaves were collected and washed with distilled water. Twelve lesion marginal tissues were sterilized with 75% ethanol (V/V) for 30 s and 1% NaOCl for 1min and rinsed with sterile distilled water, plated on potato dextrose agar (PDA) and incubated at 28°C under light. After 3 days, the incubated samples all produced similar cultural morphology. One isolate named GXMC2 as a representative was selected for following study. The colony by single-spore purification on PDA were grayish green with a white outer ring and cottony on surface, pale blackish green in reverse side (Fig.1 F). Conidia with oil droplets were solitary, cylindrical, transparent and measuring 13.78 to 19.25 μm (average 16.90 μm) × 5.14 to 7.33 μm (average 6.23 μm) (n=100) (Fig.1 G). Appressoria were brown to dark brown, with different shapes such as ovoid, elliptical or irregular, some with lobes. The average size was 7.89 to 13.25 μm (average 10.64 μm) × 5.76 to 9.02 μm (average 7.86 μm) (n=100) (Fig.1 H). No setae were found. The isolate was identified as Colletotrichum fructicola on the basis of the morphology of the colonies, conidia and appressoria (Park et al. 2018). The six target gene sequences, including internal transcribed spacer (ITS), β-tubulin (TUB), actin (ACT), histone3 (HIS3), chitin synthase A (CHS), and glyceraldehydes-3-phosphate dehydrogenase (GAPHD) (Qiu et al. 2020), were selected for PCR amplification. The resulting sequences were deposited in GenBank under accession numbers MZ821661, MZ821660, MZ821662, MZ821663, MZ821664 and MZ821665 respectively. Phylogenetic analysis of the concatenated sequences was performed with MEGA 7.0 software. The isolate was grouped in the same clade as other C. fructicola (Fig.2). In May 2022, Inoculation was conducted in the field. Four-year-old macadamia leaves were disinfected with 75% alcohol. The conidial suspension was sprayed on 5 unwounded healthy leaves, and 5 leaves sprayed with sterile distilled water served as control. The experiment was replicated 3 times, with each replicate containing 5 leaves. The average daily temperature and average daily relative humidity in the field were 30°C and 62%, respectively. After 2 days, yellow-brown spots appeared on the inoculated leaves and expanded outward. After 4 days, the diseased areas were dark brown, and the controls remained asymptomatic. The same fungal pathogen was reisolated and purified from inoculated leaves and the identity was confirmed by morphological characterization and molecular analysis, confirming Koch's postulates (Fig.1 I-J). In China, C. fructicola has been reported on Passiflora edulis Sims, Brassica parachinensis, Illicium verum, Peucedanum praeruptorum, etc. (Li et al. 2021; Yu et al. 2022; Zhao et al. 2021; Ma et al. 2020). To our knowledge, this is the first report of anthracnose of macadamia caused by C. fructicola in China. This study provides the basis for further research on this disease. https://doi.org/10.1094/PDIS-06-22-1376-PDN