The effect of trehalose, sucrose and maltodextrin addition on physicochemical and sensory aspects of freeze - dried strawberry puree

Lyoprotectant Constituents Suited for Lyophilization and Reconstitution of Stem-Cell-Derived Extracellular Vesicles

Stem-cell-derived extracellular vesicles (EVs) are emerging as an alternative approach to stem cell therapy. Successful lyophilization of EVs could enable convenient storage and distribution of EV medicinal products at room temperature for long periods, thus considerably increasing the accessibility of EV therapeutics to patients. In this study, we aimed to identify an appropriate lyoprotectant composition for the lyophilization and reconstitution of stem-cell-derived EVs. MSC-derived EVs were lyophilized using different lyoprotectants, such as dimethyl sulfoxide, mannitol, trehalose, and sucrose, at varying concentrations. Our results revealed that a mixture of trehalose and sucrose at high concentrations could support the formation of amorphous ice by enriching the amorphous phase of the solution, which successfully inhibited the acceleration of buffer component crystallization during lyophilization. Lyophilized and reconstituted EVs were thoroughly evaluated for concentration and size, morphology, and protein and RNA content. The therapeutic effects of the reconstituted EVs were examined using a tube formation assay with human umbilical vein endothelial cells. After rehydration of the lyophilized EVs, most of their generic characteristics were well-maintained, and their therapeutic capacity recovered to levels similar to those of freshly collected EVs. The concentrations and morphologies of the lyophilized EVs were similar to the initial features of the fresh EV group until day 30 at room temperature, although their therapeutic capacity appeared to decrease after 7 days. Our study suggests an appropriate composition of lyoprotectants, particularly for EV lyophilization, which could encourage the applications of stem-cell-derived EV therapeutics in the health industry.

Optimization of Conditions for a Freeze-Dried Restructured Strawberry Block by Adding Guar Gum, Pectin and Gelatin

With its high moisture content and tender texture, fresh strawberry is very susceptible to mechanical damage and microbial infection. Drying is one of the most frequently employed methods to extend its shelf life, and freeze-dried restructured strawberry block (FRSB) is an emerging popular food. Here, in order to enhance the quality of FRSB, edible gums of guar gum, pectin, and gelatin were added and the combination was optimized using response surface methodology (RSM) with chewiness, hardness, and organoleptic evaluations of the dried sample as the response indicators. The results showed that the combination addition of 0.10% guar gum, 0.22% pectin, and 0.30% gelatin contributed to the highest comprehensive quality of the dried sample. Compared with the untreated sample, the optimal combination addition of the three edible gums resulted in a higher moisture content for the dried sample (increased by 0.8%), and increased the chewiness, hardness, and porosity by 82.04%, 27.09%, and 3.01%, respectively, while maintaining more original color and forming a denser porous microstructure. The findings in the current work will be useful for the application of edible gums in freeze-dried restructured fruits and vegetables.

Application of biopolymers for improving the glass transition temperature of hairtail fish meat

BACKGROUND

Glass transition temperature (T_g ) and food moisture content are closely related, especially in foods with a high moisture content, such as surimi products. In order to improve storage condition and maintain food quality, the influence of six biopolymers on the T_g of hairtail fish meat paste was investigated by differential scanning colorimetry.

RESULTS

Samples were stored at -8 °C (>T_g ), -14 °C (T_g ) and -18 °C (<T_g ) for 105 days. The results showed that trehalose, maltodextrin and xanthan could obviously improve the T_g of the hairtail fish meat paste. Trehalose at 4.1% (w/w), maltodextrin at 5.0% and xanthan at 0.41% were determined as the optimum amounts, with the predicted value of T_g to be -14.1 °C. The total viable counts (TVC) and total volatile basic nitrogen (TVB-N) of samples stored at -14 and -18 °C were much lower and the gel strength and whiteness maintained much better than those of -8 °C.

CONCLUSION

Addition of biopolymers could effectively restrain the increase in TVC and TVB-N, as well as the dropping of gel strength and whiteness of fish meat paste during storage. A mixture of the biopolymers could improve T_g and showed great potential in the preservation of hairtail meat products. © 2017 Society of Chemical Industry.

The taste of KCl - What a difference a sugar makes

Dramatic increase in NaCl consumption lead to sodium intake beyond health guidelines. KCl substitution helps reduce sodium intake but results in a bitter-metallic off-taste. Two disaccharides, trehalose and sucrose, were tested in order to untangle the chemical (increase in effective concentration of KCl due to sugar addition) from the sensory effects. The bitter-metallic taste of KCl was reduced by these sugars, while saltiness was enhanced or unaltered. The perceived sweetness of sugar, regardless of its type and concentration, was an important factor in KCl taste modulation. Though KCl was previously shown to increase the chemical activity of trehalose but not of sucrose, we found that it suppressed the perceived sweetness of both sugars. Therefore, sensory integration was the dominant factor in the tested KCl-sugar combinations.