scholarly journals Yogurt ice cream sweetened with sucrose, stevia and honey: Some quality and thermal properties

2019 ◽  
Vol 37 (No. 6) ◽  
pp. 446-455
Author(s):  
Ayla Arslaner ◽  
Mehmet Ali Salık ◽  
Salih Özdemir ◽  
Ahmet Akköse

This study investigated the effects of some sweeteners (sucrose, honey and stevia) on the quality and thermal properties of plain (P) and cocoa (C) yogurt ice cream. For this purpose, six different yogurt ice cream samples were prepared with sucrose (control: AP, AC), with honey (BP, BC) and with stevia (CP, CC). The highest values of protein, ash, fat, lactose ratios and lightness (L*) were measured in samples with stevia. The addition of honey increased the b* values. The addition of cocoa increased pH and viscosity, but decreased overrun ratios. Although the addition of stevia reduced the lactic acid bacteria (LAB) counts, in all samples the LAB count was above 6 log CFU/g during storage. Results of the thermal and melting analysis showed that the use of stevia had a positive effect on the ice cream stability by increasing the freezing and melting point peak temperatures (Tf, Tm), the enthalpy (ΔHf, ΔHm), and the initial ice crystal melting temperatures (T’m). 

DYNA ◽  
2019 ◽  
Vol 86 (208) ◽  
pp. 117-125
Author(s):  
Luis Felipe Zambrano-Mayorga ◽  
Juan Sebastian Ramírez-Navas ◽  
Claudia Isabel Ochoa-Martínez

Thermophysical properties and the quality parameters of vanilla dairy ice cream were evaluated as a function of formulation. The sucrose were substituted for alternative sweeteners, and whey powder was used to adjust the nonfat solid content. A mixture design for four ingredients (sucrose, fructose, stevia, and whey powder) was applied. The ice cream composition was correlated with the thermophysical properties (density, viscosity, heat capacity, thermal diffusivity, and thermal conductivity). The optimal formulation, based on the quality parameters (time until first drop falls, melting time, and overrun), was determined. Additionally, the quality parameters were correlated with the thermal properties. The whey powder had a positive effect on the variables measured, improving the quality parameters. The best formulation was 12.1782 % whey powder and 0.0218 % stevia. No significant sensory instead difference was found between this formulation and a commercial ice cream sample. Sucrose was totally replaced with stevia and whey powder in the final product.


e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Corrado Berti ◽  
Annamaria Celli ◽  
Paola Marchese ◽  
Elisabetta Marianucci ◽  
Giancarlo Barbiroli ◽  
...  

AbstractSome poly(alkylene dicarboxylate)s, derived from ethanediol or 1,4- butanediol and different diacids, have been synthesized and analyzed by DSC to determine the correlations existing between the thermal properties and the length of the aliphatic chain. The polymers show crystallization and melting temperatures and enthalpies which increase as the polymethylene segments lengthen, due to the formation of more stable crystals. The samples derived from ethanediol are peculiar; they show reorganization processes during the melting and the melting temperatures are notably higher with respect to those of the other polyesters. This behavior is discussed. Isothermal analysis highlights that poly(alkylene dicarboxylate)s are fast crystallizing polymers. The Avrami analysis suggests a crystallization mechanism characterized by heterogeneous nucleation and three dimensional growth; secondary crystallizations is present only in the samples characterized by short -(CH2)- sequences, due to the reorganization of less perfect crystalline forms. A comparative study between the crystallization rates as a function of the undercooling is reported.


2015 ◽  
Vol 754-755 ◽  
pp. 71-76
Author(s):  
Mohd Firdaus Omar ◽  
Lu Yew Wei ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin

In this work, UHMWPE reinforced composites containing hybrid zinc oxide (ZnO) and chitosan particles were prepared via the hot compression technique. The effect of ZnO contents (10, 20, 30 wt.%) and chitosan contents (1, 2, 3 wt.%) on the thermal properties of UHMWPE/ZnO and UHMWPE/Chitosan-ZnO reinforced composites were successfully investigated using DSC and TGA analysis, respectively. Based on DSC results, both UHMWPE/ZnO and hybrid composites did not record significant changes in the melting temperatures (Tm). The heat fusion enthalpy (Hm) and degree of crystallinity (Xc) of hybrid composites were found to be higher than UHMWPE/ZnO composites. As the TGA results shown, hybrid composites were also found to have higher thermal stability than UHMWPE/ZnO composites at 10 % and 50 % weight loss level. Overall, the UHMWPE/ZnO + 3 wt.% Chitosan hybrid reinforced composite recorded comparable mechanical properties and better thermal properties than neat UHMWPE.


1995 ◽  
Vol 50 (4-5) ◽  
pp. 337-346
Author(s):  
W. Alexander Van Hook

Àbstract Available literature information on triple point or melting point isotope effects (and related physical properties) is subjected to thermodynamic analysis and consistency checks. New values for the melting point isotope effects for C6H6/CgD6 and c-C6H12/c-C6D12 are reported. 6Li/7Li melting point isotope effects reported recently by Hidaka and Lunden (Z. Naturforsch. 49 a, 475 (1994)) for various inorganic salts are questioned


Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 426
Author(s):  
Beatriz Adriana Salazar-Cruz ◽  
María Yolanda Chávez-Cinco ◽  
Ana Beatriz Morales-Cepeda ◽  
Claudia Esmeralda Ramos-Galván ◽  
José Luis Rivera-Armenta

The purpose of the present work was to prepare polypropylene (PP) matrix composited filled with chemically treated pistachio shell particles (PTx), and evaluate their effect on the composites’ thermal properties. PP-PTx composites were formulated in different PTx content (from 2 to 10 phr) in a mixing chamber, using the melt-mixing process. The PTx were chemically treated using a NaOH solution and infrared spectroscopy (FTIR). According to thermogravimetric analysis (TGA), the treatment of pistachio shell particles resulted in the remotion of lignin and hemicellulose. The thermal stability was evaluated by means of TGA, where the presence of PTx in composites showed a positive effect compared with PP pristine. Thermal properties such as crystallization temperature (Tc), crystallization enthalpy (∆Hc), melting temperature (Tm) and crystallinity were determinate by means differential scanning calorimetry (DSC); these results suggest that the PTx had a nucleation effect on the PP matrix, increasing their crystallinity. Dynamic mechanical analysis (DMA) showed that stiffness of the composites increase compared with that PP pristine, as well as the storage modulus, and the best results were found at a PTx concentration of 4 phr. At higher concentrations, the positive effect decreased; however, they were better than the reference PP.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chaitra Venkatesh ◽  
Yuanyuan Chen ◽  
Zhi Cao ◽  
Shane Brennan ◽  
Ian Major ◽  
...  

Abstract Poly (lactic acid)/halloysite nanotube (PLA/HNT) nanocomposites have been studied extensively over the past few years owing to the interesting properties of the polymer, PLA, and the nanoclay, HNT, individually and as composites. In this paper, the influence of the screw speed during extrusion was investigated and was found to have a significant impact on the mechanical and thermal performance of the extruded PLA/HNT nanocomposites. To determine the effect of screw speed on PLA/HNT nanocomposites, 5 and 10 wt% of HNTs were blended into the PLA matrix through compounding at screw speeds of 40, 80, and 140 rpm. Virgin PLA was compounded for comparison. The resultant polymer melt was quench cooled onto a calendar system to produce composite films which were assessed for mechanical, thermal, chemical, and surface properties. Results illustrate that in comparison to 40 and 80 rpm, the virgin PLA when compounded at 140 rpm, indicated a significant increase in the mechanical properties. The PLA/HNT 5 wt% nanocomposite compounded at 140 rpm showed significant improvement in the dispersion of HNTs in the PLA matrix which in turn enhanced the mechanical and thermal properties. This can be attributed to the increased melt shear at higher screw speeds.


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