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- Rocculi, P., et al.
(author)
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The potential role of isothermal calorimetry in studies of the stability of fresh-cut fruits
- 2012
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In: LWT - Food Science and Technology. - : Elsevier BV. - 0023-6438. ; 49:2, s. 320-323
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Journal article (peer-reviewed)abstract
- Attention is drawn to the feasibility of using high sensitivity isothermal heat conduction calorimetry to study metabolic responses of differently processed and stored fresh-cut fruit. The heat production of endogenous (tissue metabolism during 12 h of analysis at 10 degrees C for kiwifruit and strawberry) and exogenous (microbial growth during 18 d of analysis at 10 degrees C for cantaloupe) biological processes was investigated. Osmotic dehydration of fresh kiwifruit in sucrose solution (61.5 g/L) at different treatment times (30, 60 and 180 min), resulted in metabolic heat production decrease, confirming the progressive cell death induced by osmotic dehydration. Analysis on strawberry slices under two atmospheric conditions (air and innovative modified atmosphere) seemed to confirm the inhibitory effect of N2O on metabolic activity. Cantaloupe samples immersed in three different syrups (SS: sucrose syrup (20 degrees Brix); SS1: SS + 0.5 g/L ascorbic acid + 0.5 g/L citric acid; SS2: SS1 + 0.1 g/L potassium sorbate) showed a stability increase when additives with antimicrobial properties were included. Our findings confirm that isothermal calorimetry provides a versatile and high sensitive tool for conducting fundamental metabolic studies on the effect of different processing operations on the quality and shelf life of fresh-cut fruit and vegetables. (C) 2012 Elsevier Ltd. All rights reserved.
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| 4. |
- Wadsö, Lars, et al.
(author)
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Effect of tissue wounding on the results from calorimetric measurements of vegetable respiration
- 2004
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In: Thermochimica Acta. - : Elsevier BV. - 0040-6031. ; 422:1-2, s. 89-93
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Journal article (peer-reviewed)abstract
- When plant tissue is wounded a number of protective processes start. We have made a study by isothermal calorimetry of the heat production response of root and tuber tissue to wounding. Samples with different surface to volume ratios were prepared from carrots, potatoes and swedes (rutabaga) and the thermal power was measured in closed glass ampoules in a TAM Air isothermal calorimeter. The evaluation was made by assuming that a certain heat production rate per volume tissue was associated with the normal metabolic activity, and that another heat production rate per surface area was associated with the wound response. The results showed that the wound response part was high; in some cases almost half the heat came from the wound response and not from the ordinary metabolic activity. We also discuss and give some evidence that the effect seen is not caused by limited supply of oxygen to the core of our samples. This is an important factor to take into account when making calorimetry on cut biological samples. It also shows that isothermal calorimetry can be used for the study of wound response in vegetable tissue. (C) 2004 Elsevier B.V. All rights reserved.
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