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Medium 9781780647296

6 Flooding Stress Tolerance in Plants

Shabala, S. CABI PDF

6 

Flooding Stress Tolerance in Plants

chiara pucciariello* and pierdomenico perata

PlantLab, Institute of Life Sciences, Scuola Superiore Sant’Anna, Pisa, Italy

Abstract

Global warming is associated with an increase in submergence and flooding events, which makes many ecosystems worldwide vulnerable to low oxygen stress. Water submersion can severely affect crop production, since it drastically reduces the oxygen needed for plant respiration, and thus survival. Plants tolerant to flooding have evolved morphological, physiological and biochemical adaptations to oxygen deficiency. In the plant biology model species Arabidopsis thaliana, considerable progress has been made in terms of understanding the molecular aspects governing these responses and the sensing mechanism of an oxygen shortage has been identified. Many studies on oxygen deprivation stress have focused on rice (Oryza sativa), since it is one of the crops that adapts best to a flooded environment. Besides being able to germinate under submergence, rice varieties display different mechanisms for successful survival. Agronomically, the study of rice strategies to survive flooding in ecotypes that have adapted to extreme environments shows great potential in the context of climate change and the increasing global need for food.

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Phase Changes: MCAT Chemistry

Ace Academics Ace Academics ePub
Medium 9788131803660

Ch_2e

Dipak Chandra Ghosh, Nripesh Chandra Ghosh, and Prabir Kumar Haldar Laxmi Publications PDF

Jaeger

2B

Chapter

Surface Tension

2B.1

INTRODUCTION

The free surface of a liquid has a natural tendency to contract to a smallest possible area as if it is in a state of tension like a stretched membrane. Liquid drop if small in size, acquire spherical shape due to surface tension as sphere has the minimum surface area but large drop flatten out due to its weight.

The phenomenon of surface tension are closely related to the following terms:

(i) Cohesive Forces: It is the force of attraction between two molecules of similar nature. The force varies inversely as the eighth power of the distance between the two molecules. It is very strong in case of solids, weak in the case of liquids and weakest in case of gases.

(ii) Adhesive Forces: It is the force of attraction between two molecules of different substances.

Due to this force water wets a glass and cement adheres to brick.

(iii) Molecular Range: Every two molecules of matter, attract each other. The force of attraction decreases with an increase in distance. The maximum distance between two molecules so that the force of attraction remains effective is called molecular range. It is of the order, 10�7 cm.

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Medium 9781780644202

50: Vacuum-frying Processing Technology Improves Quality Attributes of Fried Sweetpotato Chips

Low, J. CABI PDF

50 

Vacuum-frying Processing

Technology Improves Quality

Attributes of Fried Sweetpotato Chips

O.P. Sobukola,* T.A. Esan, H.A. Bakare and L.O. Sanni

Federal University of Agriculture, Abeokuta, Nigeria

Abstract

Sweetpotato (Ipomea batatas) is a very important crop in developing countries. Orange-fleshed varieties provide beta-carotene, a key antioxidant and source of provitamin A. However, sweetpotato does not store for a long period unless properly cured; hence the need for processing into shelf-stable forms such as fried snacks. This study investigated the effect of sweetpotato cultivars (EX-OYUNGA, 440216 and SPK 004), type of frying oil (groundnut oil, refined, bleached and deodorized oil (RBDO) and palm oil) and vacuum frying conditions (temperature – 108°C, 122°C and 136°C, vacuum pressure – 6.54 kPa, 13.21 kPa and 19.88 kPa and time – 3 min, 6 min and 9 min) on some quality attributes of fried sweetpotato chips. The response surface methodology technique based on the Box-Behnken design was used to optimize vacuum frying processes and study the effects of the variables on quality of fried chips. Twenty-eight combinations including five replicates of centre points were performed in random order. Seven responses such as oil and moisture content, beta-carotene, texture, lightness, redness and yellowness were considered to evaluate effects of independent variables on sweetpotato chips. Fried sweetpotato chips from optimized vacuum frying conditions were compared with atmospheric fried samples using the concept of equivalent thermal driving force (ETDF). Significant differences (P < 0.05) were observed among sweetpotato varieties and frying oil type. EX-OYUNGA and groundnut oil produced chips with acceptable quality attributes. Frying temperature and time as well as vacuum pressure have significant effect on beta-carotene, texture, lightness, redness and yellowness with coefficient of determination (R2) of models for responses investigated varying between 0.7179 and 0.951. The optimized coded vacuum frying conditions for the adopted cultivar (EX-OYUNGA) and frying oil (groundnut oil) were −0.64, 1 and −1 for frying temperature, vacuum pressure and frying time, respectively, based on the desirability concept of 0838. This choice was based on fried chips of lower oil and moisture contents, higher level of beta-carotene retention, lower breaking force, lighter and intense yellow colouration. When the optimized vacuum fried samples were compared with atmospherically fried ones, the former retained about 35% beta-carotene, had improved texture, were lighter and had a more intense golden yellow colour. Hence, vacuum frying could be an alternative for producing more nutritious deep-fat fried sweetpotato chips compared with atmospheric fried samples, the dominant current practice.

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Medium 9780253355089

6. Reconstructing Body Volume and Surface Area of Dinosaurs Using Laser Scanning and Photogrammetry

Nicole Klein Indiana University Press ePub

STEFAN STOINSKI, TIM SUTHAU, AND HANNS-CHRISTIAN GUNGA

Crucial baseline data in dinosaur paleobiology and for reconstructing dinosaurs as living animals are accurate measurements of one- to three-dimensional features such as length, surface area, and volume. Dinosaur skeletons mounted and on display in museums offer the opportunity to obtain such data and to create digital models of them. These models, in turn, serve as the basis for estimating physiological and other biological parameters. In this chapter, we provide an overview of data capture using laser scanning and photogrammetrical methods and describe the working steps from the captured point clouds of the skeleton to the final volume model. Because dinosaur skeletons are complex objects with irregular structures, laser scanning proved to be much more accurate for capturing their shape than previously used methods such as photogrammetry. The modeling of the body surface area and body volume with digital techniques is also more accurate than established methods that are based on scale models. Here, nonuniform rational B spline (NURBS) curves and CAD software are used to reconstruct the body surface and for surface area and volume calculations.

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