Post-harvest Processing Of Fruit Research Articles

Comparative assessment of volatile and phenolic profiles of fresh black carrot (Daucus carota L.) and powders prepared by three drying methods

Drying is a common method in the post-harvest processing of fruits and vegetables and it can play a crucial role on the quality of the final product. This work examined the influence of three drying processes (freeze-drying: FD, intermittent microwave drying: IMWD and hot air convective drying: HACD) on the aroma and phenolic constituents of black carrot which is an essential vegetable in terms of its nutritive and health benefits. It was found that the drying process had substantial effects on the aroma and phenolic compositions of the black carrot powder samples. GC–MS analysis revealed a total of 32 volatiles in all samples. The FD samples had more numbers of aroma compounds after the fresh samples. Prevailing aroma groups were terpenes and alcohols. The highest amount of volatiles was found in the FD samples meaning that the FD played a crucial role in conserving the volatiles as compared to the HACD and IMWD. HPLC-DAD-ESI-MS/MS analysis yielded 34 constituents including 22 colorless phenolics and 12 anthocyanins. Regarding the phenolics, the highest amount was quantified in the HACD and IMWD samples. Chlorogenic acids were the major phenolic acids. The FD and IMWD caused a decline in the amount of anthocyanins while HACD resulted in an increase. Sensory analysis revealed that the FD method conserved the aroma to a greater extent and its overall acceptability was higher.

Epiphytic bacteria from withered grapes and their antagonistic effects on grape-rotting fungi

The bacterial community in the surface of withered grapes, which are partially dehydrated in the post-harvest period to produce Italian passito wine, has been seldom investigated. Fifty epiphytic bacterial strains isolated from withered berries were identified and characterized. Genera such as Bacillus, Brevibacillus, Curtobacterium, Micrococcus, Pseudomonas and Staphylococcus have been identified by comparative sequence and phylogenetic analyses of 16S rRNA gene sequences. Bacillus was predominant and several taxa within this genus have been recognized. All isolates were characterized by PCR fingerprinting and assayed for osmotic tolerance, motility and antifungal activity. Several Bacillus strains displayed antagonistic effects on grape-rotting fungi such as Botrytis cinerea, Penicillium expansum and Aspergillus uvarum. The other strains were weakly or non-antagonistic on these fungi. Assay on antagonistic interactions among bacteria was also carried out. Bacillus strains, which exhibit swimming and swarming motility, have the potential to colonize the grape surface and to compete with their neighbours for space and resources. The occurrence of these isolates could reduce the contamination of fungal pathogens during grape withering. Epiphytic antagonistic bacteria could potentially be of interest for fungal biocontrol in the post-harvest processing of fruit and vegetables.

Fruit and vegetable wash-water characterization, treatment feasibility study and decision matrices

On average, it is estimated that up to 5 L of wastewater is generated per kilogram of produce in post-harvest processing of fruit, leafy greens, and root vegetables. The typical wastewater parameters vary in concentration (solids content, COD, BOD, nitrogen, phosphorus) based on the produce being processed. The challenge for producers and regulators is that the selection of the appropriate treatment technology is challenging, so decision matrices were developed to narrow down the treatment selections. Wash-waters for different types of fruit and vegetables from two different operation types, washing only versus washing and processing were investigated. Bench-scale treatments selected for testing included settling, coagulation and flocculation with settling, centrifuge, dissolved air flotation, electrocoagulation, screening, and hydrocyclone. The developed decision matrices summarize the removal effectiveness of the different treatments for typical wastewater parameters and serve as a reference tool in understanding wash-water treatment technologies and their effectiveness in treating various wash-waters.

Membrane technology for postharvest processing of fruits and vegetables

Purpose of the review: This article reviews current membrane technology in postharvest processing of fruits and vegetables and provides practical guidelines for selecting membrane technology for postharvest processing. An overview of the current state-of-the-art membrane technology in fruit and vegetable processing and a practical guideline for designing and scaling-up membrane systems are provided. Findings: Fruit juice clarification and concentration with membrane filtration dominate current application of membrane technology in postharvest processing; however, flavor compound retention and recovery by pervaporation and osmotic distillation has started gaining foothold in the industry. Other membrane-based concentration processes show a promising future. There is a strong interest in the food research community to utilize membrane technology to recover valuable food components from waste streams. Limitations/Implications: Wide acceptance of membrane technology in the food industry is not only limited by lack of “track record”, due to relative newness of the technology, but also limited by lack of suitable membrane systems or membrane materials. Many commercial membranes and modules are designed to accommodate the needs of water treatment comm.unities (for example desalination) although there is evidence that the manufacturers are heeding the call from the food processing and biopharmaceutical industries. There is also a tendency for some individuals and membrane suppliers to exaggerate what membrane technology can accomplish and, as a result, the food industry as a whole is wary of any new membrane process that appears on the scene. Directions for future research: Future research should focus on the fundamental study of membrane fouling, particularly on interactions among biopolymers, inorganic matters, and the membrane surface. Manufacturers should develop a food-oriented evaluation and assessment protocol for constructing membrane property data sheets and improve the reliability and renew-ability of their membranes. The food science community needs to actively involve in basic research on membrane separations, not just run-of-the-mill type of study on concentration of yet another new exotic fruit (or vegetable) juice with a well-studied commercial membrane.

Applications of Electrolyzed Water in Agriculture & Food Industries

Microbial control of postharvest diseases has been extensively studied and appears to be a viable technology. Food safety must be ensured at each postharvest processing step, including handling, washing of raw materials, cleaning of utensils and pipelines, and packaging. Several commercial products are available for this purpose. The time is ripe for developing new techniques and technologies. The use of electrolyzed water (EW) is the product of a new concept developed in Japan, which is now gaining popularity in other countries. Little is known about the principle behind its sterilizing effect, but it has been shown to have significant bactericidal and virucidal and moderate fungicidal properties. Some studies have been carried out in Japan, China, and the USA on the pre- and postharvest application of EW in the field of food processing. EW may be produced using common salt and an apparatus connected to a power source. As the size of the machine is quite small, the water can be manufactured on-site. Studies have been carried out on the use of EW as a sanitizer for fruits, utensils, and cutting boards. It can also be used as a fungicide during postharvest processing of fruits and vegetables, and as a sanitizer for washing the carcasses of meat and poultry. It is cost-effective and environment-friendly. The use of EW is an emerging technology with considerable potential.