Response of different maturity stages of sapota (Manilkara achras Mill.) cv. Kallipatti to in-package ethylene absorbent
Sapota fruits are highly perishable due to their climacteric nature. The rapid softening of fruits is primarily due to high activity of many oxidative enzymes and liberation of ethylene. Harvest maturity plays a crucial role in deciding the marketability of climacteric fruits in general. Attempt has been made to evaluate the response of ethylene absorbent on variable maturity groups of harvested Sapota cv. Kallipatti with the objective to delay the ripening during transit and extend its marketability during storage at ambient condition (27–32 °C & 65–75% R.H.). Harvested fruits having three different degree of ripeness (as maturity indices viz. mature, half-ripe and ripe) were packed with or without ethylene absorbent sachets (Bioconservación, France) in 10 kg CFB boxes and transported from Dahnu to Delhi covering a distant of approximately 2500 KM by truck on road along with conventional packaging as control. The fruits were evaluated immediately on arrival at Delhi and subsequently during storage for various physical, physiological, biochemical and decay parameters. Mature fruits with ethylene absorbent exhibited maximum delay in ripening, low ethylene liberation, weight loss and high fruit firmness. The response of ethylene absorbent to extend the marketability of ripe fruit was not significant.
Preparation of a novel PdCl2–CuSO4–based ethylene scavenger supported by acidified activated carbon powder and its effects on quality and ethylene metabolism of broccoli during shelf-life
Abstract Yellowing and quality loss of broccoli is usually accelerated by ethylene. In order to remove ethylene surrounding the broccoli during shelf-life, a novel ethylene scavenger supported by acidified activated carbon powder (AACP) was developed. Results showed that acidification of the supporter might have a profound effect on ethylene scavenging. Ethylene removal rate of the palladium chloride (PdCl 2 )-impregnated AACP scavenger dramatically increased and was further promoted with the addition of copper sulfate (CuSO 4 ). The novel scavenger was optimized and prepared with AACP containing 10 mg/g PdCl 2 , 30 mg/g CuSO 4 and less than 300 mg/g moisture. Its maximum ethylene removal capacity was 21.77 mL/g at 25 °C or 20.18 mL/g at 5 °C. The ethylene removal capacity could be regenerated by 81.6% by heating at 175 °C for 20 min. The ACCP–PdCl 2 –CuSO 4 ethylene scavenger could significantly delay yellowing and quality loss of broccoli and thereby extend the shelf-life at 20 °C for 2 d. Ethylene concentration in the stored environments was decreased to 0.21 μL/L or less from 0.91 μL/L during shelf-life by the scavenger. Ethylene production, free 1-aminocyclopropane-1-carboxylic acid (ACC) content and ACC synthase activity were suppressed in the broccoli treated with the scavenger. This ethylene scavenger might eliminate ethylene to lower levels in stored environments than the threshold to trigger senescence and yellowing of the vegetable. The novel scavenger provides a promising and eco-friendly alternative to maintaining postharvest quality of broccoli and contributes to increasing its marketing value.
On the fractionation of β-lactoglobulin and α-lactalbumin
Abstract Existing methods for the preparation of α-lactalbumin and β-lactoglobulin are examined critically. It is proposed that the most satisfactory method for the preparation of the whey protein fraction from bovine milk is (NH 4 ) 2 SO 4 fractionation. A number of new gentle procedures for the fractionation of the whey proteins are compared with some existing methods. The distribution of total protein at various stages is determined by total Kjeldahl nitrogen and the kind of protein by starch-gel electrophoresis. The effect of variables, such as pH, salt concentration and temperature on the separation of α-lactalbumin and serum albumin from β-lactoglobulin is studied. Differences in the behavior ( e.g. solubility) of genetic variants of β-lactoglobulin are noted. The solubility of each of the major whey proteins, under similar conditions to those used in the fractionation, is compared with its solubility in the whey protein mixture. The understanding gained of factors important in the fractionation is used in recommending new procedures for α-lactalbumin and β-lactoglobulin isolation.