Electric Impedance, an Objective Index of Maturity in Peach

Weaver, G. M.; Jackson, H. O.

doi:10.4141/cjps66-051

Cited by 21 publications

(9 citation statements)

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“…Bioelectrical resistance was determined with a resistance meter (02-86 Shigometer) using the techniques of Weaver and Jackson (1966) as modified by Lougheed et al (1981). The two fine nickel-plated electrodes were inserted into two opposite sectors around the equatorial region of each fruit and the average of six readings for each fruit was recorded.…”

Section: Methodsmentioning

confidence: 99%

EXTENSION OF BITTER GOURD (MOMORDICA CHARANTIA L.) STORAGE LIFE THROUGH THE USE OF REDUCED TEMPERATURE AND POLYETHYLENE WRAPS

Mohammed

Wickham

1993

Journal of Food Quality

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Bitter gourd (Momordica charantia L.) fruits were stored individually wrapped in low density polyethylene (LDPE) film or unwrapped for up to 21 days at 5-7C, 20-22C and 28-30C, respectively. Assessment was done on several quality parameters including marketable quality. Storage offilm-wrapped fruit at 5-7C resulted in extension of shelf-life in excess of two weeks and delayed appearance of chilling injury symptoms. Additionally, film-wrapped fruits stored at 5-7C were still marketable after 21 days, had lowest fresh weight losses, less softening, reduced incidence ofpostharvest rots and minimal changes in vitamin C content and pH. Storage of individually wrapped fruits at reduced temperatures therefore offers an effective method of prolonging the shelf-life of bitter gourd.

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Section: Methodsmentioning

confidence: 99%

EXTENSION OF BITTER GOURD (MOMORDICA CHARANTIA L.) STORAGE LIFE THROUGH THE USE OF REDUCED TEMPERATURE AND POLYETHYLENE WRAPS

Mohammed

Wickham

1993

Journal of Food Quality

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“…A large amount of published data on electrical conductivities are reported at room temperature as they have been investigated as quality control measures to evaluate physiological processes during growth occurring in plant tissues (Sasson and Monselise 1977;Bean el al. 1960;Weaver and Jackson 1966).…”

Section: Introductionmentioning

confidence: 99%

Electrical Conductivities of Hydrocolloid Solutions

Marcotte

Piette

Ramaswamy

1998

J Food Process Engineering

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Ohmic heating was applied to solutions of 5 hydrocolloids (carrageenan, 1–3% w/w; xanthan, 1–3% w/w; pectin, 1–5% w/w; gelatin, 2–4% w/w and starch, 4–6% w/w) in a static cell to study the effect of concentration and temperature on electrical conductivities. For each experiment, the sample was poured into the cell and heated at a constant voltage gradient of 7.24 V/cm. Voltage, current, time and temperature were logged at time intervals and used to calculate electrical conductivities as a function of temperature. Of the thickening agents examined, carrageenan gave the highest value for electrical conductivity (0.2 S/m at 25C and 1% and 1.4 S/m at 100C and 3%) followed by xanthan (0.14 S/m at 25C and 1% to 1.1 S/m at 100C and 3%). Pectin and gelatin samples were found to exhibit lower, but similar electrical conductivities (0.06 S/m at 25C at the lowest concentration to 0.37 S/m at 100C at the highest concentration). Starch samples had the lowest electrical conductivity varying from 0.05 S/m at 25C and 4% to 0.21 S/m at 100C and 6%. Regression equations were established for each type of hydrocolloid solutions revealing a strong interaction between the concentration and the temperature and the electrical conductivity values. Major differences were observed between hydrocolloid types on electrical conductivities that were mainly attributed to their ash content.

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“…Numerous investigations have been carried out by electrical measurement to assess conditions of agricultural products such as variety (White et al, 1971), quality and freshness (Sugiyama et al , 1987;Kato, 1988), ripeness and maturity (Bauchot et al, 2000;Desai et al, 1977;Weaver et al, 1966), infection of virus (Greenham et al , 1952) and injury of tissues (Greenham, 1966;Zhang et al , 1993;Jiang et al , 2001). Effectiveness of impedance measurement has been shown in freezing and cold injury of agricultural products (Zhang et al , 1992(Zhang et al , , 1992Dejmek et al , 2002;Ohnishi et al , 2002).…”

Section: Introductionmentioning

confidence: 99%

Effect of Freezing on Electrical and Rheological Properties of Food Materials

Ohnishi

Shimiya

Kumagai

et al. 2004

FSTR

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Changes in electrical and rheological properties in freezing-thawing were measured and compared for various food materials, which could be classified into three groups. In the first group, plant tissue (vegetables and fruits) showed large and frequency-dependent impedance and clear characteristic Cole-Cole arc in their fresh state. These electrical properties drastically changed after freezing-thawing: impedance greatly decreased and the Cole-Cole arc disappeared, suggesting the serious change in the cell structure. Correspondingly, the dynamic elasticity and viscosity substantially decreased. In the second group, animal and fish meats showed the lower impedance and unclear Cole-Cole arc as compared with plant tissue, but these properties scarcely changed after freezing-thawing. Rheological properties were also unchanged reflecting the large freezing-tolerance for food materials in this group. In the third group, konnyaku (alimentary yam paste) and tofu (soyprotein curd) showed increase both in impedance and viscoelasticity after freezing-thawing reflecting the freezedenaturation of the major components.

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Electric Impedance, an Objective Index of Maturity in Peach

Abstract: Impedance tester and electrode probe. For personal use only.

Cited by 21 publications

References 0 publications

EXTENSION OF BITTER GOURD (MOMORDICA CHARANTIA L.) STORAGE LIFE THROUGH THE USE OF REDUCED TEMPERATURE AND POLYETHYLENE WRAPS

EXTENSION OF BITTER GOURD (MOMORDICA CHARANTIA L.) STORAGE LIFE THROUGH THE USE OF REDUCED TEMPERATURE AND POLYETHYLENE WRAPS

Electrical Conductivities of Hydrocolloid Solutions

Effect of Freezing on Electrical and Rheological Properties of Food Materials

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