Review: Enzyme inactivation during heat processing of food‐stuffs

Adams, J.B.

doi:10.1111/j.1365-2621.1991.tb01136.x

Cited by 132 publications

(56 citation statements)

References 80 publications

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“…5). E seeds, killed by long-term heat treatment that resulted in enzyme denaturation (29), allowed us to address nonmetabolic, purely physico-chemical reactions. Compared to all other nonviable seeds, heat-killed E seeds were the first to reach rT drop , related to the fastest initial water uptake, indicative of membrane degradation and massive cellular deterioration that follow heat-induced cytoplasmic glass melting (30).…”

Section: Discussionmentioning

confidence: 99%

Noninvasive diagnosis of seed viability using infrared thermography

Kranner

Kastberger²,

Hartbauer³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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Recent advances in the noninvasive analyses of plant metabolism include stress imaging techniques, mainly developed for vegetative tissues. We explored if infrared thermography can be used to predict whether a quiescent seed will germinate or die upon water uptake. Thermal profiles of viable, aged, and dead Pisum sativum seeds were recorded, and image analysis of 22,000 images per individual seed showed that infrared thermography can detect imbibition-and germination-associated biophysical and biochemical changes. These "thermal fingerprints" vary with viability in this species and in Triticum aestivum and Brassica napus seeds. Thermogenesis of the small individual B. napus seeds was at the limit of the technology. We developed a computer model of "virtual pea seeds," that uses Monte Carlo simulation, based on the heat production of major seed storage compounds to unravel physico-chemical processes of thermogenesis. The simulation suggests that the cooling that dominates the early thermal profiles results from the dissolution of low molecular-weight carbohydrates. Moreover, the kinetics of the production of such "cooling" compounds over the following 100 h is dependent on seed viability. We also developed a deterministic tool that predicts in the first 3 hours of water uptake, when seeds can be redried and stored again, whether or not a pea seed will germinate. We believe that the early separation of individual, ungerminated seeds (live, aged, or dead) before destructive germination assessment creates unique opportunities for integrative studies on cell death, differentiation, and development.aging | crop | germination | imaging | stress S eeds are attractive experimental model systems to study general biological phenomena, such as aging, cell death, and development. Desiccation tolerant "orthodox" seeds can be stored long term in the dry state, but lethal damage can be induced rapidly by "artificial aging," involving the elevation of seed moisture content (MC) and temperature (1). However, the biochemical and molecular interpretation of aging is hindered by the use of inseparable populations of viable and nonviable seeds, in which the partitioning of analytes in seeds of differential quality is unknown. Seed-quality studies would benefit from a tool that identifies individual viable and nonviable seeds before use. Moreover, global agriculture is fundamentally dependent on the production, distribution, and germination of high-quality seeds.Pioneering studies (2-7) using microcalorimetry (8, 9) demonstrated that metabolic heat flows can be used to assess gross metabolism associated with germination processes. However, microcalorimeters do not capture thermal activity in the first phase of seed imbibition while samples equilibrate in the instrument. In addition, they are closed systems, preventing dissipation of heat and gas, with potential confounding feedback on seed metabolism. Consequently, these microcalorimetric studies were inconclusive as to whether temperature rises or falls during the initial stages of s...

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Section: Discussionmentioning

confidence: 99%

Noninvasive diagnosis of seed viability using infrared thermography

Kranner

Kastberger²,

Hartbauer³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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“…Although thermal treatment inactivates effectively trypsin inhibitor, it denatures soybean proteins, results in amino acid degradation and other deteriorative reactions. Moreover, certain flavours, colours, vitamins and nutrients can also be affected by heat treatment (Adams 1991;Borhan and Snyder 1979). Therefore, inactivation of trypsin inhibitor by non-thermal pre-treatments becomes interesting to avoid quality loss of soymilk by decreasing thermal processing.…”

Section: Introductionmentioning

confidence: 99%

Effect of different process parameters on the quality of soymilk and tofu from sprouted soybean

Murugkar

2014

J Food Sci Technol

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The effect of grinding cum blanching (GCB) of sprouted soybean at different temperatures on milk and tofu quality was studied. Three temperatures (121°C-T1,100°C-T2 and 80°C-T3) for GCB were used to produce soymilk and tofu from sprouted soybean which were analysed for the yield, nutritional, anti-nutritional profile, colour attributes, particle size, organoleptic quality and texture profile. Unsprouted Soybeans with GCB at 121°C served as control (C). There was significant difference (P<0.5) in trypsin inhibitor content in milk and ranged from 4.1 mg/g in T3 to 1.4 mg/g in T1.Optimal reduction in TI of 75-80 % was achieved in T2. There was significant difference (P<0.5) in protein extractability and ranged from 84.4 % in C to 93.9 % in T2. Hardness (N) of tofu was around 11.22 in C and reduced to 8.9, 8.6 and 4.4 in T1, T2 and T3 respectively. L values of soymilk ranged from 83.4 in C to 85.8 in T3; in tofu from 83.1(T3) to 87.2 (C) and decreased with the increase in heating temperature and time. Particle size d [3, 2] and volume d [4, 3] between treatments varied significantly (P<0.0001 and P<0.0038). Overall acceptability scores on 9 point hedonic scale for all treatments for milk and tofu were above 5. The texture scores of tofu for T3 were very low due to its soft structure. From the above investigations 100°C was the optimal temperature for GCB of sprouted soybean for the production of good quality soymilk and tofu.

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“…However, the possible formation of carcinogenic chlorinated compounds in water has called into question the use of chlorine in food processing plants (Dychdala, 1991;Page, Harris, & Epstein, 1976;Wei et al, 1999). Moreover, the antimicrobial effectiveness of cold chlorinated water is limited due to hydrophobic plant surfaces that are believed to limit contact between chlorine solutions and microbial contaminants (Adams, 1991;Beuchat, 1992).…”

Section: Introductionmentioning

confidence: 99%