Soluble Pectin Content Research Articles

セイヨウナシ‘テ•フランス’の追熟生理及び品質における収穫日, 追熟温度及びエチレン処理の影響

The purpose of this study was to investigate the influence of harvest date, ripening temperature, and ethylene treatment on the ripening physiology and quality of ′La France′pears. Fruits were harvested on 3 dates (Oct. 14, 21, and 24, 1985), and then were held at 10°C, 15°C, and 20°C, respectively. Weight, flesh firmness, soluble solids, titratable acidity, total suger, soluble pectin, respiration and ethylene production were measured at harvest and during ripening.1. As harvest date was delayed, the climactric rise developed more rapidly. In the preclimactreric fruits at harvest (Oct. 14, and 21), the fruit reached the climacteric peak much earlier when held at 20°C than at 15°C and 10°C, while the magnitude of the peaks in both respiration rate and ethylene emanation were lower in the fruit held at 20°C than at 15°C and 10°C. This trend was striking in ethylene emanation.2. As harvest date was delayed and ripening temperature was raised, the number of days from harvest to full ripeness became short. No clear differences in eating quality of ripe fruits were found among those fruits, but the quality was reduced more rapidly in early-harvested fruits ripend at 20°C than in late-harvested fruits ripened at both 15°C and 10°C.3. As harvest date was delayed, total suger content became high and starch content became low at harvest. There were no differences in total suger content in fruits ripended at 20°C among different harvest dates.4. As harvest date was delayed, the maximum content of soluble pectin was reduced during ripening.5. Fruit treated with 500ppm ethylene for 24 hours at 20°C showed a higher rate of respiration, and became edible 3 to 4 days earlier than untreated fruit.6. Flesh firmness seems to be a useful indicator for harvest of′La France′pears, as it is related to ripening capacity.

Effect of Fertilization, Postharvest Handling and Blanching Temperature on the Drained Weight of Canned Summer Squash

ABSTRACTThere was no apparent effect on drained weight or firmness when three rates of calcium fertilization and two rates of potassium fertilization were applied to a test planting from which two harvests of raw summer squash were canned. However, high Ca (L2) decreased dry matter and increased structural carbohydrates and tissue Ca in the canned product. Precooling increased drained weight and dry matter, but drastically reduced firmness of the canned product. Noncooled canned squash had lower drained weights and pH, but greater firmness and higher water soluble pectin and cellulose content. Blanching at 99°C increased drained weight; blanching at 88°C decreased drained weight, but increased calgonsoluble pectin content.

Effects of Urea Sprays on the Chemical Composition of Ber Fruits (Ziziphus Mauritiana Lam.)

SummaryTrees of ber cv Banarasi Karaka were sprayed with urea solutions of 2, 4 or 6% just before flowering in September. Ripened fruits were analysed for total soluble solids, acid, sugars, vitamin C and pectin contents. The sprays caused significant increases in TSS, sugars, vitamin C and pectin contents but a decrease in the acid content of the fruit.

Preharvest Temperatures in Relation to Postharvest Quality of ‘d’Anjou’ Pears1

Abstract Quality and ripening capacity of ‘d’Anjou’ pears (Pyrus communis L.) after long-term storage were influenced by the daily-hourly average (DHA) temperatures during 6-week prior to harvest. Fruits of 17.2° and 13.9°C DHA temperatures ripened with high acid and sugar contents while samples of 20.0° and 11.7°C DHA temperature treatments failed to ripen properly and had lower quality. Failure to ripen after prolonged storage was associated with high protein nitrogen levels in the fruits. Samples of lower DHA temperature were more susceptible to friction discoloration, while fruits of higher DHA temperature had a higher percentage of superficial scald. Temperatures during this period did not appear to affect harvest maturity, size or soluble pectin content of the fruit.

異なる温度での白肉桃の追熟生理

To study the postharvest physiology of white peaches, “Okubo” and “Hakuho” peaches were held at 10°C, 15°C, 20°C, 25°Cand 30°C, respectively. Respiration, ethylene evolution, firmness, readiness of peeling, sugars, edible quality and other components of ripening were determined during ripening.1. A more rapid increase and a higher peak in ethylene evolution, an earlier peak in respiration and a more rapid attaining of readiness of peeling were observed in “Okubo” peaches ripened at 20°C than in those ripened at 25°C, whereas softening proceeded at 20°Cas rapidly as at 25°C. A few days after the respiratory climacteric peak, “Okubo” peaches ripened at 20°Cand 25°C showed a peak in ethylene evolution, followed by a rapid decline. At the respiratory climacteric peak, “Okubo” peaches were fully ripe at 20°Cand over-ripe at 25°C.2. Higher rates of ethylene evolution on the first day after harvest and a more rapid rate of softening were observed in “Hakuho” peaches than in “Okubo” peaches. An earlier peak in respiration and a more rapid rate of softening were observed in “Hakuho” peaches ripened at 25°C than in those ripened at 20°C, whereas ethylene evolution increased at 25°C as rapidly as at 20°C.3. Gradual increases in respiration and ethylene evolution and delayed softening and attaining of readiness of peeling were observed in peaches ripened at 10°C and 15°C. “Okubo” peaches ripened at 10°C and 15°C attained about the same rates of ethylene evolution and the same degrees of softening and peeling as those ripened at 25°C, while poor flavor developed at 10°C. The rates of ethylene evolution at 15°C remained relatively constant for a long period after the respiratory climacteric peak, as compared with those at 25°C. Full ripening required about three times at 10°C and two times at 15°C as much time as at 25°C.4. Ethylene evolution was suppressed and tended to decrease during ripening at 30°C. Although the respiratory climacteric failed to develope at 30°C, softening proceeded in “Hakuho” peaches as rapidly as at 25°C and it proceeded in “Okubo” peaches at a slightly slower rate than at 25°C for a few days after harvest and subsequently at approximately the same rate.5. The reducing sugar content increased gradually at 30°C during ripening. The increase in soluble pectin content seemed to be significantly related to the degree of softening.6. These data suggest the following. The ripening temperature influenced flesh color, rates of ethylene evolution and softening, and certain other ripening phenomena. Ethylene stimulated an occurrence of a respiration climacteric and other ripening reactions such as softening and readiness of peeling. Respiration, ethylene evolution, softening, readiness of peeling and other ripening reactions proceeded relating to each other during ripening, but these interrelations were influenced by factors such as variety and ripening temperature.

TECHNOLOGICAL ASPECTS OF HIGH QUALITY RAW MATERIAL OBTAINING FOR PECTIN PRODUCTION


 The article is devoted to the study of the chemical composition, physical and thermal-pfysical characteristics of damp apple pomaces and the identifying patterns of influence of drying temperature the functional composition and gel-forming ability of pectin. The research is aimed at obtaining initial data for the subsequent calculation of the main technological, hydro-mechanical, thermal, structural and economic characteristics of devices for drying the plant raw materials, ensuring the environmental safety and high quality of pectin-containing raw materials, the reducing heat and energy costs. As a result of the study of the thermal characteristics of apple pomaces, the critical points (temperature conductivity – 16.5 x 10-8 m2/s, thermal conductivity – 0.28 W/m K, heat capacity – 1627 j/(kg K)) at a humidity of 56 % are determined, which characterizing the transition from the extraction of weakly bound moisture to the extraction of moisture with strong bonds (colloidal, adsorption). It was found that the pomaces obtained from apples of late ripening have a higher content of solids (21-23 %), soluble pectin and protopectin (2.5-4.5 %). Dried pomaces obtained from apple varieties of late ripening contain up to 25 % pectin, which allow us to recommend them as a source of raw materials for the production of pectin. The optimum modes of preliminary washing of raw materials are offered, allowing to the remove the ballast substances as much as possible. It is established that when the drying temperature increases, the destructive processes are catalyzed: the strength of the pectin jelly and the uronide component and the degree of pectin esterification are reduced. The optimum drying temperature of damp apple pomaces is 80 0C, at which the quality of pectin extracted from the dried raw materials is maintained as much as possible. It is shown that the most effective for the pectin production is a fraction with a particle size of 3-5 mm, which allow us to extract up to 71 % of pectin from raw materials.

Interactions of Pectin and Protein in the Heat Coagulation of Proteins

Pectin decreases the heat coagulation of many proteins, including the soluble proteins of pea stems, ovalbumin, and bovine serum albumin. This observation probably explains the decrease in heat coagulation of proteins from pea stems following in vivo auxin administration, since auxin causes a great increase in the soluble pectin content of treated cells.