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  • Author or Editor: Robert E. Pauli x
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Abstract

Guava fruit detachment force began to decline from 7 kg at 115 days after anthesis before the fruit had fully grown, to less than 0.5 kg by day 130. There was a parallel decline in deformation force from greater than 14 kg to less than 4 kg, loss of skin chlorophyll, and a decline in pulp titratable acidity from 18 to 10 meq/100 gm fresh weight. Mature fruit harvested on one occasion showed a range of detachment force from 0.5 to 7.2 kg, which correlated well with the ranges in measures of pulp quality and fruit maturity, total soluble solids, pH, titratable acidity, and skin color. Fruit detached with a force less than 4 kg were full yellow and had pulp with a pH 3.0, less than 16 meq/100 g fresh weight titratable acidity and 6° Brix total soluble solids.

Open Access

Abstract

Composition of yam bean (Pachyrrhizus erosis L. Urb) tubers stored at 22° and 12.5°C was monitored monthly for up to 5 months. A continual loss of moisture occurred in tubers at both storage temperatures—after 4 months tubers stored at 22° lost 14.5% of their original weight; those stored at 12.5° lost 9.6%. A higher respiration rate of 15 to 28 ml·kg–1·hr–1 occurred during the first 2 months of storage at 12.5°. This was nearly double the respiration rate of tubers stored at 22°. Ethylene was not detected at any time. There are a continual breakdown of starch in tubers. After 3 months, tubers stored at 12.5° had one-sixth the harvest content of starch. At 22°, starch declined to two-thirds the harvest content. The decline in starch content at 12.5° was related to an increase in total sugars in the tuber, particularly sucrose. The sucrose content of the tuber stored at 12.5° tripled over a 3-month period. Glucose and fructose levels declined over the same period irrespective of storage temperature. The results suggest a chilling response that led to a sweeter tuber. Titratable acidity was very low, as was total phenols, and both did not change after harvest.

Open Access

Abstract

Waxing fruit of fresh pineapple [Ananas comosus (L.) Merr.] with a polyethylene-paraffin mixture influenced a number of juice characteristics as well as internal fruit atmosphere composition. Juice pH declined less and total acidity increased less with increased storage at 8°C when fruit were waxed. Total soluble solids decreased from 16° to 15° Brix with 4 weeks storage at 8° with waxing having no effect. During the 3rd week at 8°, total ascorbic acid levels decreased from an initial value of 65 mg/liter juice to less than 5mg/liter in unwaxed fruit, and to 35 mg/liter in fruit waxed with 20% v/v wax-water. Increasing wax concentration increased the retention of juice ascorbic acid. Absorbance at 267 nm in unchilled fruit was related to shell color. Juice absorbance at 267 nm decreased with storage time, with a greater decline in more mature fruit, without effect from varying wax pH or percent polyethylene. The internal fruit gas atmosphere varied with coating concentration. Increasing the length of storage time to 4 weeks at 8° increased the size of respiration peak obtained when the fruit was removed to non-chilling temperatures (22°). Unwaxed fruit at 8° had less than 1% CO2 in the fruitlet locule, while waxed fruit contained 2 to 3% CO2. Upon transfer of fruit from 8° to 22°, internal CO2 increased to near 10% in unwaxed fruit and to 15 to 20% in waxed fruit.

Open Access

Abstract

Symptoms of chilling injury (Cl) expressed as internal browning (IB) in fresh pineapple [Ananas comosus (L.) Merr.] began to appear within 2 days at 22°C after a period of storage at temperatures less than 12°. Fruit not subjected to chilling temperatures during storage also developed similiar symptoms when held for 0 to 10 days at between 18° and 30°. Fruit stored for longer than 3 weeks at temperatures of 8° and 3° showed fewer CI symptoms than similar fruit held at 12°. Waxing fruit either before or immediately after exposure to chilling temperatures was equally effective in reducing CI symptoms. Low oxygen (3%), with or without (5%) carbon dioxide during chilling did not reduce symptom expression. Storage of fruit under low oxygen following chilling significantly reduced CI symptom expression. A model for CI symptom development is presented and related to the metabolic events leading to IB of pineapple fruit, stored at chilling temperatures.

Open Access

Abstract

Lanzone (Lansium domesticum Correa) growth was sigmoidal after a delay of 100 days in which little growth occurred. Fruit growth was greatest between 115 and 130 days from anthesis, just before the pericarp changed color from green to yellow. During the 20 days that pericarp color changes occurred, there was an increase in total sugars from 30 to 180 mg·g−1 fresh weight. This change in sugars paralleled the increase in total soluble solids. Just before this period, total ethanol soluble phenols declined from 12 to 2 mg·g−1 fresh weight and was associated with loss of astringency. A slight decline in titratable acidity from 38 to 21 meq/100 g fresh weight was related to a loss of citric, malic, and succinic acids. At the edible stage, the citric and succinic acids were the major organic acids. Potassium was the major counter ion.

Open Access

Abstract

Methods were investigated to control weight loss and sprouting of stored ginger rhizome (Zingiber officinale Rosc), including waxing, sprout inhibitors, and gamma irradiation. Rhizomes stored for 3 months at 22°C and 70% RH lost about 20% weight. Waxing of the rhizome did not reduce water loss. Some wax treatments increased the number and length of sprouts. Preharvest application of maleic hydrazide significantly increased the number and reduced the length of sprouts. Postharvest CIPC application significantly reduced the length of sprouts. Vacuum infiltration increased the effectiveness of CIPC in reducing sprout length. Gamma and X-ray irradiation also reduced sprout number and length. Minimum doses of gamma radiation for sprout control was 25 Gy and 120 to 150 Gy for X-ray irradiation if the rhizome was stored for more than 3 months at 22°. A higher dose of irradiation (500 Gy) was required if complete sprout growth control was needed for storage periods <3 months at 22°. Suberization occurred during curing at 22°, but the suberin layer did not completely protect the cut surface. Chemical name used: isopropyl n-(3 chlorophenyl)-carbamate (CIPC).

Open Access

Abstract

The changes in litchi (Litchi chinensis Sonn.) growth and composition were studied in 4 cultivars; ‘Groff’ in Hawaii, and ‘Shui Dong’, ‘Gui Wei’, and ‘Mei selection’ in Guangdong, China. Fruit and aril growth showed a sigmoidal pattern while skin growth was slower and more linear. Aborted seeds in Groff and Gui Wei ceased growth early in the log growth phase. Normal seeded cultivars showed seed growth paralleling skin growth. Skin chlorophyll began to decrease logarithmically soon after the start of fruit growth increase, with anthocyanin production beginning about halfway through the growth period. During the rapid growth period, due principally to an increase in aril tissue, there was an increase in total sugars from 3% to 16%. The cultivars showed slightly different ratios of the 3 sugars identified: sucrose, glucose, and fructose. Titratable acidity was due mainly to succinic and malic acid. This acidity decreased over 2 weeks in the middle of the fruit growth period from 65 meq/100 g to 15 meq/100 g. Succinic acid decreased in the same period from about 350 meq/100 g to 0.4 meq/100 g and remained low for the remaining 40 days of development. Malic acid declined from 75 meq/100 g to 12 meq/100 g, and citric acid remained constant at around 3 meq/100 g. A major portion of the decline in succinic acid was due to dilution. Total phenols were low throughout the growth of the fruit. Mineral uptake into the fruit paralleled fruit growth, with potassium being the major cation.

Open Access