Enthalpy entropy compensation during thermal degradation of chlorophyll in mint and coriander puree

Rudra, Shalini Gaur; Singh, Harjinder; Basu, Santanu; Shivhare, U. S.

doi:10.1016/j.jfoodeng.2007.10.020

Cited by 56 publications

(42 citation statements)

References 24 publications

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“…The come-up time for each processing temperature was 20.2  3 sec due to maximized contact surface of the spiral cylinder (Fig 3). This was a considerable shorter come-up time than those reported in other studies of chlorophyll degradation during processing of plant materials which are in the order 3-4 min 24,26 . The resulting heat-treated slurry was distributed to test tubes and stored in -18°C…”

Section: Heat Treatmentsmentioning

confidence: 47%

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The effect of heat treatment of thylakoids on their ability to inhibit in vitro lipase/co-lipase activity

et al. 2014

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The effect of heat treatment of thylakoids on their ability to inhibit in vitro lipase/colipase activity.Östbring, Karolina; Rayner, Marilyn; Sjöholm, Ingegerd; Otterström, Jennie; Albertsson, PerÅke; Emek, Sinan Cem; Erlanson-Albertsson, Charlotte General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal AbstractThylakoids has been shown to prolong lipolysis by the inhibition of lipase/co-lipase, which makes thylakoids suitable as a functional food ingredient with satiating properties. The components of thylakoids that provide its function as a lipolysis modulator are primarily photosystems I and II, which are structurally stabilised by chlorophyll. However, chlorophyll is known to be heat sensitive yet the enzymatic inhibiting capacity after heat treatment has not been previously studied. It was hypothesised that the retained function of thylakoids after heat treatment could be correlated to the degree of degradation. Heat treatment at either 60°C, 75°C or 90°C for time interval ranging from 15 sec to 120 min induced a color shift from bright green to olive brown which was attributed to degradation. The ability of heat-treated thylakoids to inhibit lipolysis in vitro was also reduced. A correlation between chlorophyll a degradation and the enzymatic inhibiting capacity could be established which opens possibilities to use a spectrophotometric method to quantify the ability of thylakoids to inhibit lipase/co-lipase in a more rapid and cost effective way to complement the pH-stat method used today. With the degradation pattern investigated, it is then possible to design a thermal treatment process to ensure a microbiological safe appetite-reducing product and at the same time minimize the loss of functionality.

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Section: Heat Treatmentsmentioning

confidence: 47%

“…This phenomenon has been studied in a wide 8 variety of vegetables as spinach, mint, coriander, broccoli and peas 24,25 . Chlorophyll degrades to either pheophytin (by heat or acid) or to pheophorbide (by enzymatic breakdown and heat).…”

Section: Functional Consequences Of Heat Treatmentmentioning

confidence: 99%

The effect of heat treatment of thylakoids on their ability to inhibit in vitro lipase/co-lipase activity

et al. 2014

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“…Such reactions are classified as "fast," for example neutralization of a strong acid with a strong base in solutions. It turns out in a number of cases that a growing linear dependence between E A and the change of entropy ΔS / = for the formation of the activated complex from the reagents is observed in similar reactions [24][25][26].…”

Section: Theoretical Approach and Mathematical Backgroundmentioning

confidence: 97%

“…In this case, the reactivity is high, and the system can react faster to produce the activated complex, which gives shorter observed reaction times [22,23]. Studies of the kinetics of a number of similar chemical reactions, both homogeneous and heterogeneous, show that there is a growing linear dependence between the activation energy E A and the change of the entropy ΔS / = at the formation of the activated complex from the reagents [24][25][26]. The establishment of these linear dependences in the studies of the kinetics of similar reactions can be regarded as a proof that the applied kinetic equation describes the specifics of the limiting stage and, furthermore, the kinetic parameters characterizing the process have been correctly calculated.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Nonisothermal Degradation of Some Polymer Composites: Change of Entropy at the Formation of the Activated Complex from the Reagents

Turmanova

Genieva

Vlaev

2011

Journal of Thermodynamics

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Studying the nonisothermal kinetics of degradation of rice husks in air or nitrogen atmosphere, polypropylene and tetrafluoroethylene-ethylene copolymer filled with different quantities of rice husks flour or the products of its thermal degradation, namely "white" or "black" rice husks ash, a linear dependence was observed between the ln A and E A , known as the kinetic compensation effect or theta rule. A linear relationship was also established between E A and the change of the entropy ΔS / = for the formation of the activated complex from the reagents. These dependences are related to the assumption of identical kinetic mechanisms of thermal degradation of the composites studied. The negative values of ΔS / = obtained show that the activated complex is a "more organized" structure than the initial reactants and that these reactions may be classified as "slow" ones. It may be concluded that the products of the thermal degradation of rice husks in a fluidized bed reactor can successfully replace the more expensive synthetic fillers to obtain different polymer composites. These polymer composites can lead to the futuristic "organic-inorganic hybrid materials" with specific properties.

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“…Some chemical and biochemical reactions such as browning reactions and lipid oxidation may alter the final color (Okos, Campanella, Narsimhan, Singh, & Weitnauer, 2007). Temperature, power level and drying time are the main factors affecting the color changes during drying (Rudra, Singh, Basu, & Shivhare, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Ismail¹,

Kocabay²

2018

Turk. J. Fish. Aquat. Sci.

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Rainbow trout (Oncorhynchus mykiss) fillets were subjected to microwave and infrared drying. For microwave drying, four different microwave power levels of 90, 180, 270 and 360 W were used, while for infrared drying, three different infrared power levels of 83, 104 and 125 W were used. A comparison of the drying kinetics showed microwave drying to be more effective for shortening the drying time that was required to reach a certain moisture content when compared with infrared drying. For determination of drying kinetics of fish, the experimental data for moisture content changes with time were evaluated using various empirical drying models while the effective diffusion coefficient was evaluated using Fick's law of diffusion. The activation energy values of fish samples dried by microwave drying were relatively higher than those for infrared drying. The logarithmic model was found to be the most suitable in describing the drying characteristics of rainbow trout fillets. Kinetic parameters for the color change were determined using Hunter "L", "a", "b" values and total color difference values. "L" and "b" values increased and "a" value decreased after drying. The Hunter color parameters changed more with infrared drying.

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Enthalpy entropy compensation during thermal degradation of chlorophyll in mint and coriander puree

Cited by 56 publications

References 24 publications

The effect of heat treatment of thylakoids on their ability to inhibit in vitro lipase/co-lipase activity

The effect of heat treatment of thylakoids on their ability to inhibit in vitro lipase/co-lipase activity

Kinetics of Nonisothermal Degradation of Some Polymer Composites: Change of Entropy at the Formation of the Activated Complex from the Reagents

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