scholarly journals Effects of Isochoric Freezing Conditions on Cut Potato Quality

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 974
Author(s):  
Yuanheng Zhao ◽  
Cristina Bilbao-Sainz ◽  
Delilah Wood ◽  
Bor-Sen Chiou ◽  
Matthew J. Powell-Palm ◽  
...  

Isochoric freezing is a pressure freezing technique that could be used to retain the beneficial effects of food storage at temperatures below their freezing point without ice damage. In this study, potato cylinders were frozen in an isochoric system and examined using full factorial combinations of three processing procedures (immersed in water, vacuum-packed and immersed in ascorbic acid solution), four freezing temperatures/pressures (−3 °C/37 MPa, −6 °C/71 MPa, −9 °C/101 MPa and −15 °C/156 MPa) and two average compression rates (less than 0.02 and more than 0.16 MPa/s). The effects of process variables on critical quality attributes of frozen potatoes after thawing were investigated, including mass change, volume change, water holding capacity, color and texture. Processing procedure and freezing temperature/pressure were found to be highly significant factors, whereas the significance of the compression rate was lower. For the processing procedures, immersion in an isotonic solution of 5% ascorbic acid best preserved quality attributes. At the highest pressure level of 156 MPa and low compression rate of 0.02 MPa/s, potato samples immersed in ascorbic acid retained their color, 98.5% mass and 84% elasticity modulus value. These samples also showed a 1% increase in volume and 13% increase in maximum stress due to pressure-induced hardening.

1989 ◽  
Vol 54 (10) ◽  
pp. 2644-2647 ◽  
Author(s):  
Petr Schneider ◽  
Jiří Rathouský

In porous materials filled with water or water solutions of inorganic salts, water freezes at lower temperatures than under normal conditions; the reason is the decrease of water vapor tension above the convex meniscus of liquid in pores. The freezing point depression is not very significant in pores with radii from 0.05 μm to 10 μm (about 0.01-2.5 K). Only in smaller pores, especially when filled with inorganic salt solutions, this depression is important.


2009 ◽  
Vol 2 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Nurten Ozsoy ◽  
Eda Candoken ◽  
Nuriye Akev

In order to demonstrate whether the known biological effects ofAloe vera(L.) Burm. fil. could correlate with the antioxidant activity of the plant, the antioxidant activity of the aqueous leaf extract was investigated. The present study demonstrated that the aqueous extract fromA. veraleaves contained naturally occuring antioxidant components, including total phenols, flavonoids, ascorbic acid, β-carotene and α-tocopherol. The extract exhibited inhibitory capacity against Fe3+/ascorbic acid induced phosphatidylcholine liposome oxidation, scavenged stable DPPH•, ABTS•+and superoxide anion radicals, and acted as reductant. In contrast, the leaf inner gel did not show any antioxidant activity. It was concluded that the known beneficial effects ofAloe veracould be attributed to its antioxidant activity and could be related to the presence of phenolic compounds and antioxidant vitamins.


PLoS ONE ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. e0205535 ◽  
Author(s):  
Marcia Rodrigues da Silva ◽  
Adriana Schapochnik ◽  
Mayara Peres Leal ◽  
Janete Esteves ◽  
Cristina Bichels Hebeda ◽  
...  

2012 ◽  
Vol 32 (2) ◽  
pp. 223-227
Author(s):  
Aynur Batkan ◽  
Akif Kundakçi ◽  
Bülent Ergönül

In this research, the effects of three different holding periods (6, 12 and 24 hours) prior to storage on the quality attributes of Starking Delicious apples were investigated during storage of 8 months at 0.5 ± 1.0 ºC. Changes in weight loss, flesh firmness, pH values, soluble dry matter amount, titratable acidity values, ascorbic acid contents, and total and reducing sugar content were determined. According to the results, the holding period showed statistically significant changes in the quality attributes of the apples (p < 0.05).


2017 ◽  
Vol 47 (11) ◽  
pp. 2773-2792 ◽  
Author(s):  
Chen Cheng ◽  
Zhaomin Wang ◽  
Chengyan Liu ◽  
Ruibin Xia

AbstractThe ice shelf water (ISW) plume is a prevalent phenomenon at the base of an ice shelf or sea ice adjacent to the ice shelf front. Such plumes may become supercooled and deposit marine ice when they rise. In the existing frazil ice–laden ISW plume models, it is generally assumed that supercooling and frazil ice growth can be adequately treated by using depth-averaged freezing temperature and vertically uniform frazil ice concentration within a plume. In reality, however, the temperature deficit and frazil ice concentration both increase toward the top of the plume. Hence, frazil crystals typically experience a greater deficit than that suggested by the plume’s temperature subtracted from its depth-averaged freezing point. In this study, the authors considered the combined nonlinear effects of vertical structures of frazil ice concentration and thermal forcing within an ISW plume by introducing equilibrium vertical profiles of frazil ice concentration into a horizontal two-dimensional depth-integrated ISW plume model. A series of idealized numerical experiments and an observation-based simulation beneath the western side of Ronne Ice Shelf have been conducted by using the vertically modified and original depth-integrated ISW plume models. It was found that the supercooled area, supercooling level, and suspended frazil ice and marine ice productivities are all substantially underestimated by the original models. Moreover, the differences are sensitive to the selected frazil ice size configuration. These results suggest that the vertical modification introduced in this study can significantly improve simulated marine ice distribution and its corresponding production, in comparison with those estimated by previous depth-integrated models.


1994 ◽  
Vol 267 (6) ◽  
pp. R1646-R1652
Author(s):  
A. Arav ◽  
B. Rubinsky

We have developed a new device that measures freezing and melting temperatures in nanoliter volume samples and can be used as a "freezing point osmometer" with a resolution many orders of magnitude greater than that of existing freezing point osmometers. Using this device we found anomalies in the depression of the freezing temperature and thermal hysteresis in aqueous solutions of hydrophilic amino acids, polyamino acids, and lectins. These anomalies would not have been possible to detect with currently used technology. The compounds that produce anomalies in freezing temperature were reported in the literature as having the ability to bind to cell membranes. This suggests a relation between a molecule's ability to bind to cell membranes and its anomalous freezing temperature depression. The new freezing point osmometer and our results could be important for studying and understanding organic molecules and their interaction with membranes and water.


1956 ◽  
Vol 34 (1) ◽  
pp. 1251-1260 ◽  
Author(s):  
André DesMarais

The effect of ascorbate administration on resistance to cold and thyroid function was studied in adrenalectomized rats receiving various amounts of cortisone and/or DCA; in thyroidectomized rats given different doses of of thyroxine, the effect of ascorbate administration was evaluated on both resistance to cold and adrenal function.In adrenalectomized rats given large doses of cortisone (2.5 mgm.) and exposed to cold, the administration of either ascorbate (150 mgm.) or DCA (2.5 mgm.) enhances the survival, reduces the extent of thymolysis, and decreases the activation of the thyroid. In adrenalectomized rats receiving no cortisone or DCA or low doses (0.4 and 0.1 mgm.) of these hormones, ascorbate administration (150 mgm.) still retains some of its beneficial effects on resistance to cold (better growth and survival); when low doses of DCA (0.1 mgm.) are given without cortisone, ascorbate administration seems to have a deleterious effect on the growth and survival during exposure to cold, with a greater increase in thyroid activity.In thyroidectomized rats exposed to cold, ascorbate administration (150 mgm.) has no effect in the absence of thyroxine, but increases the efficiency of low doses (3 μgm.) of thyroxine, preventing at the same time some of the typical signs of an alarm reaction: thymolysis and adrenal enlargement.These results are interpreted as showing that the role of the cortical hormones in resistance to cold might be limited to a "conditioning" action and that the beneficial effects of ascorbate administration would be mediated through the thyroid hormones.


Author(s):  
Theodoros Papathanasiou ◽  
Nikolaos Gougoulias ◽  
Vayos G. Karayannis ◽  
Christina-Anna Kamvoukou

The aim of the current research was to investigate and compare the total phenolic content and antioxidant capacity of sweet pepper cultivars at different development and maturation stages, in order to optimize the beneficial effects. For that purpose, three important sweet pepper cultivars, namely Dolmy-F1, Yahoo-F1 and Florinis-NS-700, were cultivated in a greenhouse. Their total phenolic content, ascorbic acid content and antioxidant properties were assessed at different development and maturation stages. In the aforementioned cultivars, the total phenolic content ranged from 345.2 to 602.1, 404.9 to 794.5, and 795.7 to 2220.3 μg GAE g−1 FW respectively. The ascorbic acid content ranged from 236 to 957, 258 to 1157, and 410 to 1550 μg AA g−1 FW respectively. The highest antioxidant activity was noted at the red maturity stage. Particularly the cultivar Florinis NS 700 was found to possess higher total phenolic, flavonoid phenol, non-flavonoid phenol, ascorbic acid contents, and greater antioxidant capacity, compared to the other cultivars. The results of our study recommend the consumption of the sweet peppers at red maturity stage, for achieving the maximum health-beneficial effects.


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