Changes in physical and gelling properties of freeze-dried egg white as a result of temperature and relative humidity.

Background: The quality of dried egg white with respect to functional properties can be affected by storage conditions. The effect of temperature and relative humidity (RH) on changes in colour and gelling properties in freeze-dried egg white (FDEW) during storage was investigated.

Results: The glass transition temperature (Tg ) of FDEW decreased with increasing % RH.

The effect of moisture content on physicochemical properties of extruded waxy and non-waxy rice flour.

The properties of waxy rice flour (WRF) and non-waxy rice flour (RF) were modified using an extrusion process with different feeding material moisture contents. WRF was more affected by the thermomechanical stress from extrusion; consequently, it had a lower glass transition temperature but higher water solubility index (WSI) indicating higher molecular degradation than extruded RF. The lower moisture content of the feeding flour caused more severe flour damage (coarser surface of the extruded flour) and lowered relative crystallinity compared to higher moisture content processing.

Influence of waxy rice flour substitution for wheat flour on characteristics of batter and freeze-thawed cake.

This study aimed to improve the freeze-thawed cake properties by10-20% waxy rice flour (WRF) substitution for wheat flour (WF). Viscosity of WRF-substituted batters was lower; consequently, trapped air was less uniformly distributed than WF batter. After five freeze-thaw cycles, firmness and enthalpy of melting retrograded amylopectin of WF- and WRF-substituted cakes increased and the matrix surrounding the air pores from SEM images was denser than in fresh-baked cakes.

Effects of freezing and thawing on texture, microstructure and cell wall composition changes in papaya tissues.

Background: During storage, frozen fruit may be thawed and refrozen many times before consumption, which may be extremely damaging to the texture of the frozen fruit and reverse the advantage of fast freezing. The effects of freezing and thawing on texture, microstructure and cell wall composition changes in papaya tissues were investigated.

Results: The frozen-thawed papayas had an increase in drip loss and a decrease in firmness with increasing number of freeze-thaw cycles.

Retrogradation of Waxy Rice Starch Gel in the Vicinity of the Glass Transition Temperature.

The retrogradation rate of waxy rice starch gel was investigated during storage at temperatures in the vicinity of the glass transition temperature of a maximally concentrated system (T g '), as it was hypothesized that such temperatures might cause different effects on retrogradation. The T g ' value of fully gelatinized waxy rice starch gel with 50% water content and the enthalpy of melting retrograded amylopectin in the gels were investigated using differential scanning calorimetry. Starch gels were frozen to -30°C and stored at 4, 0, -3, -5, and -8°C for 5 days.

Porosity and water activity effects on stability of crystalline β-carotene in freeze-dried solids.

Unlabelled: Stability of entrapped crystalline β-carotene as affected by water activity, solids microstructure, and composition of freeze-dried systems was investigated. Aliquots (1000 mm(3) , 20% w/w solids) of solutions of maltodextrins of various dextrose equivalents (M040:DE6, M100:DE11, and M250:DE25.5), M100-sugars (1:1 glucose, fructose and sucrose), and agar for gelation with dispersed β-carotene were frozen at -20, -40, or -80 °C and freeze-dried.

Reversed phase HPLC analysis of stability and microstructural effects on degradation kinetics of β-carotene encapsulated in freeze-dried maltodextrin-emulsion systems.

Degradation of dispersed lipophilic compounds in hydrophilic solids depends upon matrix stability and lipid physicochemical properties. This study investigated effects of solid microstructure and size of lipid droplets on the stability of dispersed β-carotene in freeze-dried systems. Emulsions of β-carotene in sunflower oil were dispersed in maltodextrin systems (M040/DE6, M100/DE11, and M250/DE25.

Effect of waxy rice flour and cassava starch on freeze-thaw stability of rice starch gels.

Repeatedly frozen and thawed rice starch gel affects quality. This study investigated how incorporating waxy rice flour (WF) and cassava starch (CS) in rice starch gel affects factors used to measure quality. When rice starch gels containing 0-2% WF and CS were subjected to 5 freeze-thaw cycles, both WF and CS reduced the syneresis in first few cycles.

Texture improvement of fresh and frozen mangoes with pectin methylesterase and calcium infusion.

Background: A major problem of mango products is texture loss. The effect of commercial pectin methylesterase (PME) and calcium infusion on improvement of the texture of both fresh and frozen-thawed mango cubes was investigated in the present study.

Results: The weight gain and moisture content of mango samples were greater at relatively high vacuum level (10 kPa).

The effect of rice aging on the freeze-thaw stability of rice flour gels.

This study investigated the effect of aging rice on the freeze-thaw stability of rice flour gels since repeated freeze-thaw cycles can lead to reduced food quality. A rice grain cultivar called 'Khoa Dawk Mali 105' was aged for three different time periods, ranging from 0 to 12 months. Rice gels made from the aged rice were then freeze-thawed for up to 5 cycles.