Biochemical and Visual Changes in Cactus Stems (Opuntia ficus-indica Mill.) Stored at 4, 12 and 26C

Abstract

The purpose of this study was to identify visible and microscopic symptoms as well as certain biochemical changes associated with chilling injury (CI) in "Atlixco" cactus stems. Cladodes were harvested, disinfected, minimally processed and stored at 4, 12 and 26C for 14-21 days. Results indicated that cactus stems were sensitive to CI at 4 and 12C and exhibited pitting and bronzing as visible symptoms of this disorder. Confocal microscopy showed that mitochondrial integrity was maintained at 4C whereas a deterioration of these organelles occurred at 12 and 26C. Electrolyte leakage, together with an increase in the levels of Adenosine triphosphate (ATP), glutathione and the reduced form of ascorbic acid were associated with CI. In spite of the presence of CI at 4C, cactus stems were still able to preserve their taste quality and no adverse effects were observed on either firmness or color for 21 days. PRACTICAL APPLICATIONSMinimally processed products should be refrigerated at ≤4C in order to maintain their quality and prevent the growth of harmful microorganisms. However, the refrigeration of cactus stems at suboptimal temperatures causes the appearance of chilling injury (CI). Previous studies have mentioned the general symptoms of this physiological disorder in cactus stems, but no one has described the symptomatology in detail and there is yet to be reported histological and biochemical characterization that might serve to confirm or diagnose its presence. This study describes the symptoms of CI and provides histological and biochemical indicators for its early identification during storage. It also constitutes the preliminary stage to the future application of postharvest technologies that induce tolerance to CI, preventing browning and preserving the quality of minimally processed cactus stems in order to expand their domestic and international markets.

Cactus stem (Opuntia ficus‐indica Mill): anatomy, physiology and chemical composition with emphasis on its biofunctional properties

“…In relation to the postharvest life of minimally processed cactus stems stored under different temperatures, Rodríguez‐Verástegui et al . studied their cellular structure and the damage caused to the epidermis.…”

“…Thus, it is recommended to consume younger cactus stems in order to help regulate blood sugar levels and accelerate nutrient absorption in the gut. 49 In relation to the postharvest life of minimally processed cactus stems stored under different temperatures, Rodríguez-Verástegui et al 50 studied their cellular structure and the damage caused to the epidermis. They reported that the cactus stems without thorns and stored at 26 ∘ C, presented a break-up in the cellular structure and water loss after 7 days, resulting in a product with a fibrous texture associated with water loss.…”

Thermal treatment and modified atmosphere packaging delay chilling injury and preserve the quality of cactus stems (Opuntia ficus-indicaMill.) cv Atlixco

“…Additionally, as was previously discussed, the use of a CO 2 ‐rich atmosphere also enabled the preservation of most of the original green color in Atlixco stems, particularly when compared with the other two atmospheres analyzed (i.e., 100% N 2 and air). In this sense, past studies have concluded that CO 2 does significantly delay the senescence of chloroplasts (at least in banana peels, Song et al, ), and it is quite telling that such organelles are particularly abundant in the chlorenchymal tissues of cactus stems (Rodríguez‐Verástegui et al, ). These two explanations could therefore be the reasons behind the results obtained with the 10% CO 2 + 90% N 2 atmosphere.…”

“…A 400 μl sample of this elute was additionally mixed with 100 μl of dithiothreitol (DTT, Sigma‐Aldrich) at 5% (w/v), kept in the dark overnight at room temperature, and used to quantify DHA. Analysis of both compounds was performed on an Agilent 1260 Infinity HPLC (Santa Clara, CA) according to the conditions of operation described by Rodríguez‐Verástegui et al (). Measurements were made at 254 nm (Nour, Trandafir, & Ionica, ) using a variable multiple wavelength detector (VMWD).…”

“…CI negatively impacts the quality of many horticultural products that have been stored at suboptimal temperatures for relatively long periods of time. Previously, our research group described the symptoms of CI in MP‐cactus stems of the variety Atlixco (Rodríguez‐Verástegui et al, ). In that report, we presented evidence of the many macroscopic and microscopic alterations that characterize this disorder over time.…”