Drying of Tarhana dough by Refractance Window™ technology under vacuum/atmospheric conditions: Characterization of physical and quality parameters.

This study aimed to produce dried tarhana using a refractance window drying (RWD) system. The drying process was also carried out under vacuum; the current study is the first in the literature. Using different heating mediums, the maximum temperature can be adjusted to a level above that used in RWD studies. Considering results, process time savings in RWD were over 85% and 75% compared to control groups (oven and hot air dryer), respectively. Tarhana samples dried in RWD were also faster (50%) under vacuum conditions than atmospheric ones. The highest preservation of total phenolic content (TPC) and total antioxidant activity (TAA) was for samples dried by RWD at 110°C under atmospheric conditions. Techno-physical properties were better than the control group. The rheological behavior of tarhana soups was similar to pseudoplastic flow behavior and well defined by the Power law and Herschel-Bulkey models. In conclusion, RWD can be a promising technique for tarhana production.

Use of ohmic heating as an alternative method for cooking pasta.

BACKGROUND: In this study, the alternative method of ohmic heating (OH) was applied to investigate its potential usage in the cooking process for pasta and its comparison with the conventional method. For this purpose, OH was operated at four different voltage gradients (10, 20, 30, 40 V cm-1 ). The electrical conductivity of pasta σ (S m-1 ) was calculated for the temperature range 22-95 °C and a three-phase linear relation between σ and temperature was determined. RESULTS: According to the results, the energy consumption of the OH system and cooking time were lower than the conventional method. Energy conservation was about 73.7% at 40 V cm-1 and increased up to 90.4% (at 10 V cm-1 ) with lower voltage gradients. Total cooking time, cooking loss, water absorption, degree of gelatinization, volume uptake, energy consumption and sensorial properties were investigated. No significant differences between the results of samples cooked with the conventional method and OH at 30-40 V cm-1 were found in terms of starch gelatinization degree, volume change, water absorption, and sensorial analysis (P > 0.05). CONCLUSION: These results revealed that OH did not cause any negative effects on the quality parameters of pasta samples, and positive effects were observed on energy and time saving. © 2021 Society of Chemical Industry.

Optimisation of pre-drying and deep-fat-frying conditions for production of low-fat fried carrot slices.

BACKGROUND: The main objective of the current study was to reduce the fat content of fried carrot slices with a hot air pre-drying step before frying. In this regard the effects of hot air drying and deep-fat-frying conditions on moisture and oil contents, breaking force and colour parameters of pre-dried and fried carrot slices were investigated. RESULTS: Statistical analysis with response surface methodology showed that there was a significant correlation between investigated responses and process variables (P ≤ 0.05). Based on the optimal conditions (63.4 °C for drying temperature, 16% for weight loss, 152 °C for frying temperature, and 207 s for frying time) produced by the optimisation of process conditions, more than 50% reduction in fat content of fried carrot slices was achieved by hot air pre-drying before frying. CONCLUSION: The results presented indicated that the proposed cooking method is useful to control final oil content of fried carrot slices, so indirectly limiting the daily calorie intake by consumers without spectacular losses in quality attributes. © 2016 Society of Chemical Industry.

Aroma transition from rosemary leaves during aromatization of olive oil.

The aroma profile of aromatized olive oil was determined in this study. The primary objective was to investigate the transition of major aroma compounds from rosemary and olive fruit during the kneading step of olive oil production by response surface methodology. For this purpose, temperature, time, and amount of rosemary leaves were determined as independent variables. The results indicated that temperature and time did not affect the transition of target compounds, but rosemary leaves addition had a strong influence on transition, especially for characteristic aroma compounds of this herb. Adequacies of developed models were found to be high enough to predict each aromatic component of interest.

Evaluation of Two Fitting Methods Applied for Thin-Layer Drying of Cape Gooseberry Fruits

ABSTRACT Drying data of cape gooseberry was used to compare two fitting methods: namely 2-step and 1-step methods. Literature data was also used to confirm the results. To demonstrate the applicability of these methods, two primary models (Page, Two-term-exponential) were selected. Linear equation was used as secondary model. As well-known from the previous modelling studies on drying, 2-step method required at least two regressions: One is primary model and one is secondary (if you have only one environmental condition such as temperature). On the other hand, one regression was enough for 1-step method. Although previous studies on kinetic modelling of drying of foods were based on 2-step method, this study indicated that 1-step method may also be a good alternative with some advantages such as drawing an informative figure and reducing time of calculations.

Optimization of solid-liquid extraction of resveratrol and other phenolic compounds from milled grape canes (Vitis vinifera).

Optimization of the solid-liquid extraction conditions for trans-resveratrol, trans--viniferin, ferulic acid, and total phenolics from milled grape canes has been investigated. The temperature and ethanol concentration were found to be major process variables for all responses, whereas the solvent to solid ratio was found not to be significant for any of the responses studied. The yields of trans-resveratrol, trans--viniferin, and total phenolics increased with increasing temperature. Maximum yields of trans-resveratrol (4.25 mg/g dw), trans--viniferin (2.03 mg/g), and total phenolics (9.28 mg/g dw) were predicted from the combination of a moderate ethanol concentration (50-70%) and the highest temperature (83.6 degrees C), whereas an ethanol concentration of 35% at the lowest temperature studied (16.4 degrees C) was optimal for the extraction of ferulic acid (1.05 mg/g dw). Effective diffusivity values of resveratrol in the solid phase, D eff for different extraction conditions, were calculated by fitting the experimental results to a model derived from the Fick's second law. Effective diffusivity of resveratrol in the solid phase varied from 3.1 x 10 (-13) to 26.6 x 10 (-13) m (2) s (-1) with changing extraction conditions. The increase in effective diffusivity of resveratrol was observed with increasing temperature, and the highest predicted level was obtained when using 54% ethanol/water mixture at 83.6 degrees C. The increase in ethanol concentration exhibited the favorable effect up to 50-55%, thereafter effective diffusivity decreased with a further increase in concentration.