Emerging chemical and physical disinfection technologies of fruits and vegetables: a comprehensive review.

With a growing demand for safe, nutritious, and fresh-like produce, a number of disinfection technologies have been developed. This review comprehensively examines the working principles and applications of several emerging disinfection technologies. The chemical treatments, including chlorine dioxide, ozone, electrolyzed water, essential oils, high-pressure carbon dioxide, and organic acids, have been improved as alternatives to traditional disinfection methods to meet current safety standards. Non-thermal physical treatments, such as UV-light, pulsed light, ionizing radiation, high hydrostatic pressure, cold plasma, and high-intensity ultrasound, have shown significant advantages in improving microbial safety and maintaining the desirable quality of produce. However, using these disinfection technologies alone may not meet the requirement of food safety and high product quality. Several hurdle technologies have been developed, which achieved synergistic effects to maximize lethality against microorganisms and minimize deterioration of produce quality. The review also identifies further research opportunities for the cost-effective commercialization of these technologies.

Chemical and physical pretreatments of fruits and vegetables: Effects on drying characteristics and quality attributes - a comprehensive review.

Pretreatment is widely used before drying of agro-products to inactivate enzymes, enhance drying process and improve quality of dried products. In current work, the influence of various pretreatments on drying characteristics and quality attributes of fruits and vegetables is summarized. They include chemical solution (hyperosmotic, alkali, sulfite and acid, etc.) and gas (sulfur dioxide, carbon dioxide and ozone) treatments, thermal blanching (hot water, steam, super heated steam impingement, ohmic and microwave heating, etc), and non-thermal process (ultrasound, freezing, pulsed electric field, and high hydrostatic pressure, etc). Chemical pretreatments effectively enhance drying kinetics, meanwhile, it causes soluble nutrients losing, trigger food safety issues by chemical residual. Conventional hot water blanching has significant effect on inactivating various undesirable enzymatic reactions, destroying microorganisms, and softening the texture, as well as facilitating drying rate. However, it induces undesirable quality of products, e.g., loss of texture, soluble nutrients, pigment and aroma. Novel blanching treatments, such as high-humidity hot air impingement blanching, microwave and ohmic heat blanching can reduce the nutrition loss and are more efficient. Non-thermal technologies can be a better alternative to thermal blanching to overcome these drawbacks, and more fundamental researches are needed for better design and scale up.

Transformation of cell wall pectin profile during postharvest ripening process alters drying behavior and regulates the sugar content of dried plums.

This study evaluated the effects of postharvest ripening (0-6 days, D0-6) on cell wall pectin profile, infrared-assisted hot air-drying characteristics, and sugar content. Results showed that during postharvest ripening progress, the content of water-soluble pectin (WSP) and chelate-soluble pectin (CSP) increased while the content of Na2CO3-soluble pectin (NSP) and hemicellulose (HC) decreased. In addition, the average molecular weight of WSP increased while the average molecular weight of NSP decreased. Secondly, the drying time of plums with different postharvest ripening periods was in the order: D3 < D4 < D2 < D1 < D0 < D5 < D6. Furthermore, the sugar content of dried plums was mainly influenced by drying time, with three stages of sugar changes observed, tied to moisture content: (1) Sucrose hydrolyzes (50-85%); (2) Fructose and glucose degrade (15-50%); (3) Sorbitol degrades (15-42%). These findings indicate that the transformation of cell wall pectin profile during the postharvest ripening process alters drying behavior and regulates the sugar content of dried plums. CHEMICAL COMPOUNDS STUDIED IN THIS ARTICLE: Galacturonic acid (PubChem CID: 439215); Acetone (PubChem CID: 180); Distilled water (PubChem CID: 962); Trans-1,2-Diaminocyclohexane-N, N, N, N'-tetraacetic acid (PubChem CID: 2723845); Na2CO3 (PubChem CID: 10340); Glucose (PubChem CID: 5793); fructose (PubChem CID: 2723872) sucrose (PubChem CID: 5988) sorbitol (PubChem CID: 5780) and Sodium borohydride (PubChem CID: 4311764).

Thermal Decontamination Technologies for Microorganisms and Mycotoxins in Low-Moisture Foods.

The contamination risks of microorganisms and mycotoxins in low-moisture foods have heightened public concern. Developing novel decontamination technologies to improve the safety of low-moisture foods is of great interest in both economics and public health. This review summarizes the working principles and applications of novel thermal decontamination technologies such as superheated steam, infrared, microwave, and radio-frequency heating as well as extrusion cooking. These methods of decontamination can effectively reduce the microbial load on products andmoderately destruct the mycotoxins. Meanwhile, several integrated technologies have been developed that take advantage of synergistic effects to achieve the maximum destruction of contaminants and minimize the deterioration of products.

Characteristics of smokers and predictors of quitting in a smoking cessation clinic in Guangzhou, China.

BACKGROUND: Smoking cessation programs are well established in the West, but reports on smoking cessation clinics (SCCs) from China are lacking. On the basis of the Hong Kong experience and with strong support from Guangzhou Health Bureau, we established the first SCC in Guangzhou, China. The objective was to describe the characteristics of smokers, measure quit rates and examine predictors of successful quitting. METHODS: During 2006-08, 220 smokers received individual counseling following the five A's and five R's. No medications were used. RESULTS: At baseline, the mean (SD) age was 40 (14) years. Most (96%) were males, married (73%), currently employed (75%), college educated or above (54%); 77% had previous quitting attempts. By 14 May 2008, 195 reached the 6 months follow-up period. Of them, 79% (151/195) were successfully followed up, and 46 had quit. By intention to treat, the 6-month 7-day point prevalence quit rate was 24% [95% confidence interval (CI) 18-30%]. Smokers with more confidence in quitting or were at action stage were more successful in quitting with adjusted odds ratio of 2.39 (95% CI 1.01-5.30) and 5.50 (95% CI 1.08-28) respectively. CONCLUSIONS: A pilot-model clinic free of charge and with systemic data collection, follow-up and evaluation should be a starting point for smoking cessation program in low-income countries.

Effects of ripening stage on physicochemical properties, drying kinetics, pectin polysaccharides contents and nanostructure of apricots.

Effects of ripeness (four stages from the lowest to highest degree-I, II, III, and IV) on the physicochemical properties, pectin contents and nanostructure, and drying kinetics of apricots were investigated. The color values (L*, a*, and b*) and total soluble solid content increased during ripening, while the titratable acidity content and hardness decreased. The water-soluble pectin content increased as ripening progressed, but the chelate- and sodium carbonate-soluble pectin contents gradually declined. Atomic force microscopy imaging indicated that the pectin depolymerization occurred during ripening. Fruits at stage III obtained the highest drying rate, and the drying time was reduced by 27.27%, 17.24%, and 7.69% compared to those of stage I, II and IV, respectively. Results showed that the ripeness had significant influence on the drying kinetics, which is related to the modification of physicochemical and pectic properties. The ripeness classification is an essential operation for achieving effective drying process.

High-humidity hot air impingement blanching alters texture, cell-wall polysaccharides, water status and distribution of seedless grape.

Blanching pretreatment plays an essential role in fruits and vegetables processing to obtain excellent final products. The purpose of current work was to characterise the texture, cell-wall polysaccharides and water distribution of grapes pre- and post- high-humidity hot air impingement blanching (HHAIB). The cell-wall pectins nanostructure, water status and distribution of samples were determined by atomic force microscopy (AFM), low field nuclear magnetic resonance (LF-NMR) and magnetic resonance image (MRI), respectively. Results revealed that blanching caused significant berry tissue softening which was accompanied by an increase of water-soluble pectin (WSP, from 39.57 to 57.44 g/100 g fresh weight) and a decrease of chelate-soluble pectin (CSP, from 79.34 to 53.78 g/100 g fresh weight) and sodium-carbonate-soluble pectin (NSP, from 364.23 to 187.64 g/100 g fresh weight) concentration. Obvious depolymerization and degradation was observed in cell-wall polysaccharides nanostructure in blanched berries. The length frequencies of WSP chains are mainly distributed in the range of 0.51-2.00 µm, while it was 1.01-2.00 µm for the CSP chains of blanched samples. LF-NMR transverse relaxation time and MRI analysis indicated that HHAIB treatment resulted in a water loss and migration from berry interior to surface tissue. The findings in present study provide a deeper understanding in tissue softening and moisture variation of blanched berries.

High humidity hot air impingement blanching (HHAIB) enhances drying rate and softens texture of apricot via cell wall pectin polysaccharides degradation and ultrastructure modification.

The effects of high humidity hot air impingement blanching (HHAIB) over a range of application times (30, 60, 90, and 120 s) on drying characteristics, hardness, cell wall pectin fractions contents and nanostructure, as well ultrastructure of apricot were investigated. Results showed that HHAIB reduced drying time and decreased the hardness of apricot by 20.7%-34.5% and 46.57%-71.89%, respectively. The water-soluble pectin (WSP) contents increased after blanching, while the contents of chelate-soluble pectin (CSP) and sodium-carbonate-soluble pectin (NSP) decreased significantly (P < 0.05). The hardness and drying time were found to correlate inversely with the WSP content, but positively with CSP and NSP contents. Atomic force microscopy (AFM) detection showed the decomposition and degradation of pectin fractions during blanching. Additionally, transmission electron microscopy (TEM) observation indicated that the cell wall structure was degraded and middle lamella integrity was destroyed by blanching.