Ohmic Heating: Thermal Processing of Fruits and Vegetables

Author(s):  
M. Sivashankari ◽  
Akash Pare
2012 ◽  
Vol 2 (4) ◽  
pp. 136-140
Author(s):  
P. Hema Prabha ◽  
U. Kavya Vaishnavi ◽  
R. Mythili ◽  
M. Lakshmi Kamu ◽  
R. Kanagalakshmi ◽  
...  

Ohmic heating is an emerging technology with large number of actual and future applications. It is an advanced thermal processing method wherein the food material, which serves as an electrical resistor, is heated by passing electricity through it. Like thermal processing, ohmic heating inactivates microorganisms by heat. It can be used for heating liquid foods containing large particulates, heat sensitive liquids and proteinaceous foods. The shelf life of ohmically processed foods is comparable to that of canned and sterile, aseptically processed products. Being an eco‐friendly method it is more effective than conventional thermal processing methods.


2010 ◽  
Vol 73 (3) ◽  
pp. 425-433 ◽  
Author(s):  
TIMOTHY C. ELLS ◽  
LISBETH TRUELSTRUP HANSEN

Mild thermal processing can enhance the shelf life of cut fruits and vegetables by delaying the onset of spoilage and preserving the organoleptic properties of shredded cabbage. However, food safety issues related to this process have not been fully investigated. Therefore, the survival and growth of Listeria spp. on cabbage treated in this manner was examined. Experimentally, 24 strains of Listeria spp. (including L. monocytogenes) were inoculated onto cut and intact cabbage tissues and stored at 5°C. All strains on intact tissues exhibited a moderate decline in numbers (up to 1.0 log CFU/cm2) over the 28-day storage period. Conversely, cut tissue supported growth of most strains during the first 7 to 14 days of incubation with maximum increases of 1.2 log CFU/cm2. Subsequently, the survival or growth on heat-treated (50°C for 3 min) and untreated shredded cabbage of four L. monocytogenes and four nonpathogenic Listeria spp. strains were compared during storage for 21 days at 5°C. Growth on untreated shred for all strains was similar to the results observed on cut tissue with a maximum increase of approximately 1.0 log CFU/g. However, in the heat-treated cabbage shred all strains displayed a rapid increase in growth (up to 2.5 log CFU/g) during the first 7 days of incubation, which may be indicative of the destruction of an endogenous growth-inhibiting compound within the cabbage. In conclusion, this study shows that mild thermal treatments of cut cabbage may promote pathogen growth if other inimical barriers are not implemented downstream of the thermal treatment.


2020 ◽  
Vol 10 (19) ◽  
pp. 6802
Author(s):  
Abdo Hassoun ◽  
Shikha Ojha ◽  
Brijesh Tiwari ◽  
Turid Rustad ◽  
Heidi Nilsen ◽  
...  

Muscle food products play a vital role in human nutrition due to their sensory quality and high nutritional value. One well-known challenge of such products is the high perishability and limited shelf life unless suitable preservation or processing techniques are applied. Thermal processing is one of the well-established treatments that has been most commonly used in order to prepare food and ensure its safety. However, the application of inappropriate or severe thermal treatments may lead to undesirable changes in the sensory and nutritional quality of heat-processed products, and especially so for foods that are sensitive to thermal treatments, such as fish and meat and their products. In recent years, novel thermal treatments (e.g., ohmic heating, microwave) and non-thermal processing (e.g., high pressure, cold plasma) have emerged and proved to cause less damage to the quality of treated products than do conventional techniques. Several traditional assessment approaches have been extensively applied in order to evaluate and monitor changes in quality resulting from the use of thermal and non-thermal processing methods. Recent advances, nonetheless, have shown tremendous potential of various emerging analytical methods. Among these, spectroscopic techniques have received considerable attention due to many favorable features compared to conventional analysis methods. This review paper will provide an updated overview of both processing (thermal and non-thermal) and analytical techniques (traditional methods and spectroscopic ones). The opportunities and limitations will be discussed and possible directions for future research studies and applications will be suggested.


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