Evaluation of Biochemical and Quality Attributes to Monitor the Application of Heat and Cold Treatments in Tomato Fruit (Lycopersicon Esculentum Mill.)

Abstract

The study was accomplished to optimize the application of stress treatment to prevent chilling injury (CI) in tomatoes. Four treatments were evaluated: control, heat shock applied for 24 (HS24) and 48 h (HS48), and cold shock applied for 24 h (CS24). The fruits were stored at 2 and 14C, and evaluated immediately after treatment and after 21 and 28 days of storage. An additional evaluation after 7 days of exposure at 20C following storage withdrawal was included to induce ripening and exteriorize the development of CI symptoms. Different biochemical and quality attributes were evaluated (color, titratable acidity, firmness, ethylene, CI index and heat shock protein [HSP] accumulation). Heat treatments were successful in preventing the decay of fruits under CI-inducing conditions. The significantly better performance of HS48 in comparison to the other treatments gives evidence that the effectiveness relies on the adequate intensity of application; therefore, this intensity should be strictly controlled by a proper monitoring method. In this regard, small HSP accumulation was found suitable to reflect properly the physiological condition of fruits and therefore to potentially optimize and determine the adequate intensity of treatment application. PRACTICAL APPLICATIONSStress treatments constitute a promising technological alternative to extend the shelf life of fruits and vegetables because of their capacity to prevent the development of chilling injury during the cold storage of sensitive species. The main advantages are the ease of use, considering that they can be applied in commercial chambers with minor changes, and the avoidance of chemicals. By assessing the effectiveness of treatments and the suitability of different biochemical and quality attributes as monitoring parameters to maximize the efficiency of application, it became apparent that the adequate intensity of application must be accurately established, since beyond a certain limit, the effect of the stress may induce irreversible alterations, provoking a permanent damage. The study provides evidence that small heat shock protein accumulation constitutes suitable monitoring parameters to objectively establish the optimal intensity, able to maintain the quality characteristics and extend the shell life of tomatoes during the cold storage. Journal of Food Quality

Effect of infield handling conditions and time to pre-cooling on the shelf-life and quality of tomatoes

“…Firmness was measured according to the procedure described by Polenta et al (2015). Briefly, the fresh fruit firmness (FFf) of six tomato fruits from each replicate was assessed using a durometer (Analog HP mechanical fruit firmness tester, Lauderdale, Florida, USA).…”

Distinct Tomato Cultivars Are Characterized by a Differential Pattern of Biochemical Responses to Drought Stress

“…These results confirm the protective role of HSP70 in drought and osmotic stress and show that the most tolerant tomato cultivars respond by increasing the HSP70 content to restore cell function and recover from drought stress. An increase in HSP70 content has been repeatedly observed under abiotic stress conditions, for example in tomatoes subjected to high temperatures [56] and in sugarcane under drought stress conditions [14]. Although the increase in HSP70 under abiotic stress is not actually surprising, the difference observed between tomato cultivars is noteworthy; this again highlights how different genotypes can exhibit different responses in terms of chaperone proteins.…”

Comparison of different analytical methods to evaluate the heat shock protein (HSP) response in fruits. Application to tomatoes subjected to stress treatments

“…This information is valuable from the technological point of view, considering that, as shown in previous studies, the amount of the induced proteins properly reflects the level of stress undergone by tissues. Among the different studies on this subject, the level of overexpression of HSP were used to evaluate and monitor the optimal protection induced by stress treatments in chilling sensible commodities such as tomatoes ( Polenta et al., 2015 ), citrus ( Polenta et al., 2007 ), banana ( He et al., 2012 ) and avocado ( Kassim et al., 2013 ). In this last commodity, Florissen et al.…”

“…In the field of postharvest technology of fruits and vegetables, HSP constitutes the principal marker to evaluate the level of protection exerted by heat treatments, applied to prevent the development of chilling injury and other physiological and pathological distresses in sensitive commodities. In this regards, different studies were carried out in fruit species such as avocado ( Florissen et al., 1996 ), tomatoes ( Ré et al., 2017 ; Polenta et al., 2007 , 2015 ; Aghdam et al., 2015 ; Aghdam and Bodbodak, 2014 ), peaches, plums, bananas, and grapefruits ( Aghdam et al., 2013 ; Aghdam and Bodbodak, 2014 ).…”