Optimisation of convective drying of carrots using selected processing and quality indicators

Abstract

Summary The effect of drying temperature (40–65 °C) and air rate (2–6 m s−1) on the formation of Maillard reaction indicators and vitamins content of carrots dehydrated by convection has been investigated. The range of assayed processing conditions, based on a previous central composite face design (CCD), led to moderate changes in the studied parameters, even under the most severe conditions. In addition, the drying kinetic of the process was studied taking into account the experimental quantitation of shrinkage, which allowed the determination of a first drying period with a constant rate of water evaporation per unit of exchange surface. The slope of the first drying period, the moisture loss during the first hour of drying and the level of quality parameters (Maillard reaction indicators and vitamins) were correlated with processing conditions with high accuracy. For the prototype here used, the optima temperature and air rate to maximise the desirability function (0.77) were 46 °C and 4.9 m s−1.

Investigation of dynamic quality changes and optimization of drying parameters of carrots (Daucus carota var. laguna)

“…The same experimental design was reported by Ogolla et al () for spray drying of camel milk. To obtain the regression coefficients, the experimental data were fitted to a second‐order polynomial model indicated by Equation (13), with the general linear model approach: where β 0 , β i , β ii , and β ij are the regression coefficients for the intercept and the linear, quadratic, and interaction terms, respectively, while y is the response, x i and x j are the independent variables, and ε is the non‐explainable portion of variation (Gamboa‐Santos, Soria, Fornari, Villamiel, & Montilla, ; Myers, Montgomery, Vining, Borror, & Kowalski, ). The coefficient of determination ( R 2 ) was chosen to fit the polynomial equation.…”

Preparation of citrus pectin gels by power ultrasound and its application as an edible coating in strawberries

“…The analysis of 2‐furoylmethyl‐lysine (furosine) was determined by ion‐pair reversed‐phase high‐performance liquid chromatography in a furosine‐dedicated C 8 column and an ultraviolet detector at 280 nm, based on the method of Gamboa‐Santos et al …”

“…The coating forming solutions were based on pectin gels at 3% (w/v) prepared as it described previously for the rheological analysis of samples (Samples and gel preparations section). Strawberries were coated by hand‐immersion for 2 min and the excess was dripped off for 30 s, and then the edible film was dried by convection using a computer controlled air tray dryer (SBANC, Edibon, Spain) with air rate control (AVE, 2–6 m s −1 ) at room temperature for 30 min . Control samples were not coated to enable a comparison of the effect of the coating on the fruit.…”

“…Protein content was determined in a colorimetric analysis by the Bradford method (Bradford kit; Bio-Rad Laboratories Gmbh, München, Germany). 17 The analysis of 2-furoylmethyl-lysine (furosine) was determined by ion-pair reversed-phase high-performance liquid chromatography in a furosine-dedicated C 8 column and an ultraviolet detector at 280 nm, based on the method of Gamboa-Santos et al 18 To determine the DM of pectin samples, Fourier-transform infrared spectroscopy (FT-IR) was carried out using a Bruker IFS66v spectrometer. The spectra were recorded at absorbance mode from 7000 to 550 cm −1 (mid infrared region) at a resolution of 4 cm −1 .…”

“…Strawberries were coated by hand-immersion for 2 min and the excess was dripped off for 30 s, 21 and then the edible film was dried by convection using a computer controlled air tray dryer (SBANC, Edibon, Spain) with air rate control (AVE, 2-6 m s −1 ) at room temperature for 30 min. 18 Control samples were not coated to enable a comparison of the effect of the coating on the fruit. All samples were stored in polystyrene boxes over 5 days at 4 ∘ C.…”