Histological Effects of Calcium Chloride in Stored Apples

Abstract

<jats:p>Mature apples (<jats:italic>Malus domestica</jats:italic> Borkh. cv. Golden Delicious) were immersed for 2 min in 0, 0.14, 0.27, or 0.41 mol·L<jats:sup>−1</jats:sup> (0, 2%, 4%, or 6%, respectively) aqueous solutions (w/v) of CaCl<jats:sub>2</jats:sub> at 0 or 68.95 kPa, and were stored at 0 °C. Histological samples of peel/cortex were taken at harvest and at four monthly intervals in storage. Paraffin sections were stained with an aqueous mixture of alcian blue 8GX, safaranin 0 and Bismark brown Y, or with the periodic acid-Schiff (PAS) reaction. No histological difference was observed in fruit treated with 2% CaCl<jats:sub>2</jats:sub> compared with those pressure-infiltrated with greater amounts of Ca. Fruits pressure-infiltrated with 6% CaCl<jats:sub>2</jats:sub> exhibited the greatest amount of flattened epidermal cells and hypodermal cavities. Cuticles were also affected at the higher CaCl<jats:sub>2</jats:sub> treatment levels (with regard to staining with Bismark brown), becoming more condensed and uniform. Cuticle and hypodermis were stained differentially with PAS in the 6% CaCl<jats:sub>2</jats:sub> treatment. All tissues, including the cuticle, were stained magenta red, indicating a possible chemical alteration of the cuticle and the underlying tissue by Ca.</jats:p>

Effect of calcium chloride in combination with salicylic acid on post-harvest freshness of apples

“…Many physiological and pathological disorders of apples are associated with the calcium content of fruit tissues. Therefore, the storability of apples and fruits is closely related to the calcium content (6,18). CaCl 2 can be used as a quality protective agent for apples to maintain Ca contents, total soluble solid contents, titratable acidity, ascorbic acid contents, and firmness.…”

“…Calcium applications can reduce the respiratory intensity and ethylene release rate of post-harvest apples, and can delay senescence (6). Moreover, post-harvest treatment of apples with calcium chloride (CaCl 2 ) may delay softening and reduce the incidence of physiological disorders, such as bitter pit and flesh browning (6,7) and both pre-harvest spraying with CaCl 2 and post-harvest infiltration of CaCl 2 solution can reduce the symptoms of brown rot (8).…”

Preharvest calcium chloride application improves postharvest keeping quality of tomato (Lycopersicon esculentum Mill.)

“…In tomato, deficiency of calcium causes blossom-end rot and cracking (Simon, 1978). In general, the direct application of calcium to the fruit is the most effective method for increasing fruit calcium content, which could be accomplished by preharvest sprays, postharvest dips or vacuum or pressure infiltration (Trentham et al, 2008). Foliar treatment of CaCl2 on tomato is known to result in greater flesh firmness, quicker development of red colour, higher weight loss and soluble solids content (Garcia et al, 1995).…”

Drying Habanero Pepper (Capsicum chinense) by Modified Freeze Drying Process

“…The histological cutting preparation was made following the next steps: Fixation: treat the tissue with chemical substances to keep the properties of the organic tissue intact, inactivating enzymes that degenerate the tissue.Washing: The excess fixative is removed. Clarification: After dehydrating the tissue, a liquid paraffin solution is passed as an inclusion medium and xylene or xylol as a miscible medium [19].Inclusion: The tissue sample is placed in a container and molten paraffin is added at 60 • C, placing the sample in an oven 30 min at 60 • C for 6 h.Cut: The cube obtained can be cut into sections thin enough to allow the passage of light, having a thickness of 5-10 micrometers.Mounting: Using a mounting solution, 1% gelatin at 38 • C, using it as an adhesive for the strip obtained from cutting on a slide.Coloring: To be observed under a microscope, it must be colored or contrasted [20].…”