scholarly journals Influence of drying temperature and ultrasound application in some quality properties of apple skin.

Author(s):  
Juan A. Cárcel ◽  
Matheus P. Martins ◽  
Edgar J. Cortés ◽  
Susana Simal ◽  
Antonio Mulet ◽  
...  

The great amount of waste produced by the food industry can be an interesting source of bioactive compounds. To this end, convective drying is one of the most extended method to stabilize the industrial by-products. However, drying conditions can affect not only drying kinetics but also the bioactivy of some compounds. Apple skin constitutes one of the main by-product generated in apple juice or cider production. It contains important amounts of functional compounds such as polyphenols or vitamin C whose extraction can be interesting. The main aim of this work was to determine the influence of drying conditions, temperature and application of ultrasound, in some quality parameters of dried apple skin. For this purpose, apple skin samples were dried at different temperatures (-10, 30, 50 and 70 ºC) and with (20.5 kW/m3) or without application of ultrasound. Color, total phenolic content, antioxidant activity and vitamin C was measured in fresh and dried samples. The increase of drying temperature and the ultrasound sligthly reduced the antioxidant properties of samples while no influence in sample color was observed. Keywords: by-product; antioxidant; polyphenol; vitamin C; color.

Author(s):  
Ronaldo Elias de Mello-Júnior ◽  
Nathane Silva Resende ◽  
Jefferson Luiz Gomes Corrêa ◽  
Leila Aparecida Salles Pio ◽  
Elisângela Elena Nunes Carvalho

Dekopon or Hallabong (Citrus reticulate “Shiranui”) is a hybrid fruit that belongs to the citrus fruits. The scientific and commercial interests in dekopon is due to its nutritional composition. The objective of the study was to verify the influence of ethanol as a pretreatment in reducing drying time as well as maintaining nutritional quality (vitamin C, total phenolic compounds, and antioxidant activity) of dekopon slices. The drying with ethanol at 70 °C promoted the greatest reduction in drying time, but the processed pretreated samples at 50 °C presented the highest level of nutritional quality parameters. Keywords: drying time; vitamin C; phenolic compounds; antioxidant activity 


Author(s):  
Juan A. Cárcel ◽  
Matheus P. Martins ◽  
Edgar J. Cortés ◽  
Carmen Rosselló ◽  
Ramón Peña

The great amount of waste produced by food industry contains interesting bioactive compounds. The extraction of these compounds requires the by-products previous stabilization being the convective drying one of most used techniques to this end. Drying conditions can affect both drying kinetics and final quality of products. The apple skin, byproduct of apple juice or cider industries, is rich in functional compounds such as polyphenols or vitamin C. The main goal of this contribution was to quantify the influence of temperature and ultrasound application in drying kinetics of apple skin. For this purpose, drying experiments at different temperatures (-10, 30, 50 and 70 ºC) and with (20.5 kW/m3) and without application of ultrasound were carried out. Drying kinetics were modelled by using a diffusion based model. As can be expected, the higher the temperature the faster the drying. Ultrasound application accelerated the process at every temperature tested being the influence slightly lower than found from the literature for other products. This can be attributed at the physical structure of the apple skin, less porous than the pulp. In any case, the application of ultrasound significantly reduced the drying time. Keywords: by-products; dehydration;diffusivity; mass transfer


2018 ◽  
Vol 46 (1) ◽  
pp. 128-133 ◽  
Author(s):  
Ferit CELIK ◽  
Mehmet Ramazan BOZHUYUK ◽  
Sezai ERCISLI ◽  
Muttalip GUNDOGDU

In present study, fruit weight, fruit firmness, external fruit color, soluble solid content, pH, titratable acidity, vitamin C, total phenolics, total anthocyanins, and antioxidant capacity of eight wild bilberry grown in Coruh valley in northeastern Turkey were determined. The blueberry cv. ‘Bluecrop’ is also included study to make comparison with bilberry genotypes. Antioxidant activity of bilberry and blueberry fruits were comparatively assessed by FRAP (Ferric reducing antioxidant power) assay. Significantly higher content of phenolics and anthocyanins was found in bilberry fruits than in blueberry fruits. However blueberry cv. ‘Bluecrop’ exhibited higher fruit weight and vitamin C content than bilberry fruits. Total phenolic and total anthocyanin content was 327 mg gallic acid equivalent and 142 mg of cyanidin-3-glucoside equivalent in 100 g fresh fruit in cv. ‘Bluecrop’ while it was between 492-563 mg gallic acid equaivalent and 307-342 mg of cyanidin-3-glucoside equivalent in 100 g fresh fruits of  bilberry accessions. Moreover, wild accessions approximately had 2-3 folds higher antioxidant capacity than cv. ‘Bluecrop’. Results suggest the possibility of improving the bioactive and antioxidant properties of bilberry cultivars based food products by using wild ones in cross breeding. It was also concluded that genotypes significantly affect their bioactive content and consequently the possibility of using wild bilberry fruits as a potential source of natural antioxidants in food industry.


2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Pongdanai Duangsai ◽  
Somsamorn Gawborisut

Fermented fish dip is a popular condiment in Thailand and the Lao People’s Democratic Republic. Thai fermented fish dip (TFFD), can be dried to increase its shelf life and ease of transportation. Dried TFFD can be rehydrated to return the powder to its original, paste-like form. Pre-cooked TFFD paste was dried at three different temperatures (40, 60, and 80 ºC). Total plate count, yeast and mold count, CIE colour values (L*, a*, and b*),non-enzymatic browning, and sensory scores of the resulting powders were determined. The CIE colour values and sensory scores were alsoanalysed for rehydrated TFFD. Increasing the drying temperature did not affect the total plate count or yeast and mold count. When dried at 80 ºC, the L* value of TFFD powder was reduced, although the a* and b* values were unaffected compared with lower temperatures. All CIE colour values of rehydrated TFFD decreased as drying temperature increased. Drying temperature did not affect the sensory scores of dried TFFD powder. However, rehydrated samples that had been dried at 80 ºC had significantly lower sensory colour scores than those dried at 40 or 60 ºC. Overall preference rankings of dried and rehydrated TFFD dried at 40 and 60 °C were better than for those dried at 80 °C. Due to an undesirable colour change in the rehydrated product, 80 ºC was deemed to be an unsuitable temperature for drying TFFD paste. In conclusion, both 40 and 60 ºC are appropriate temperatures for drying the product.


Author(s):  
Raquel P. F. Guine ◽  
Mariana F. S. Brito ◽  
Jéssica R. P. Ribeiro

AbstractThe present work aimed at studying the mass transfer properties of two plant foods, kiwi (a fruit) and eggplant (a vegetable). For this convective drying experiments were conducted at different temperatures (from 50 to 80 ºC) and an air flow rate of 0.5 m/s, using slices with 6 mm thickness for both products. For the mathematical modelling two different methods were used, one based on the thin layer model and the other based on the Fick’s second law of diffusion. The results obtained allowed concluding that different methodologies allowed to obtain different values of the mass transfer properties, so care must be taken when choosing an appropriate calculation method. Regarding the values of diffusivity and mass transfer coefficient, in all cases they were found to increase with increasing operating temperature. Both the activation energy and the activation energy for convective mass transfer were similar for kiwi and for eggplant, indicating that both foods behave in a very similar way when exposed to the drying conditions tested.


2021 ◽  
Vol 33 (1) ◽  
pp. 1-15
Author(s):  
Begüm Tepe ◽  
Raci Ekinci

Drying kinetics, water-soluble vitamins, total phenolic content (TPC), antioxidant capacity (AC) of the jujube fruits dried at 50, 60, and 70°C, and degradation kinetics of the quality parameters were investigated. The models fitted to drying were determined as Page at 50 and 70°C, Parabolic at 60°C. Increment in the drying temperature increased the drying rate and decreased the drying time. Water-soluble vitamins, TPC, and AC were significantly reduced by the drying process. Degradation of water-soluble vitamins increased with the drying temperature, although TPC and AC were not significantly affected by temperature. Thermal degradations of quality parameters were fitted to first-order kinetic.


2018 ◽  
Vol 192 ◽  
pp. 03041
Author(s):  
Setthawat Thanimkarn ◽  
Ekkapong Cheevitsopon ◽  
Jiraporn Sripinyowanich Jongyingcharoen

This study aimed to investigate the effect of drying temperature (40, 60, 80, and 100°C) on drying characteristics of Cissus quadrangularis Linn. (CQ) undergoing convective drying. Physical properties and phytochemicals of the dried CQ were also evaluated. CQ with the thickness of 5 mm was dried from about 10 to 0.1 g water/g dry matter. The results showed that increasing drying temperature increased drying rate (DR) and effective moisture diffusivity (Deff) and consequently decreased drying time. The drying time, maximum DR, and Deff were in the ranges of 85-1920 min, 0.0059-0.0248 g water/g dry matter·min, and 0.7302-9.1281×10-9 m2/s, respectively. Lower drying temperature could preserve quality of the dried CQ. Decreasing drying temperature resulted in greener and lower bulk density and shrinkage. The greatest total phenolic content (TPC) and quercetin content were obtained by drying the CQ at 60°C.


2018 ◽  
Vol 47 (1) ◽  
pp. 99-107 ◽  
Author(s):  
Lee-Hoon Ho ◽  
Nor Fadhilah Ramli ◽  
Thuan-Chew Tan ◽  
Norlia Muhamad ◽  
Mohd Nizam Haron

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1706 ◽  
Author(s):  
Anton Rahmadi ◽  
Yuliana Sabarina ◽  
Sukmiyati Agustin

Background: Mandai, the fermented inner skin of cempedak (Artocarpus integer), may have further use as industrial ingredient while maintaining its antioxidative capacity. To promote fermentation, Lactobacillus casei was induced as the starter culture. This research was carried out (i) to investigate the effect of temperature on yield, chemical properties, and antioxidant activity of starter induced fermented mandai powder, (ii) to find the best drying temperature for the powder, and (iii) to find correlations between phenolic contents and antioxidant activity of the powder. Methods: The drying temperature was used as the variable, and was set at 45, 50, and 55°C at a fixed duration of 18 hours. The control was spontaneously fermented mandai dried at 50°C for 18 hours. Total phenolic content (TPC), hydrolyzed tannic content (HTC), and total flavonoid content (TFC) were spectrophotometrically measured, expressed gallic acid (GAE), tannic acid (TAE), and catechin (CAE) equivalents. Antioxidant capacity was measured by DPPH assay.  Results: The best mandai powder had total phenolic content of 348.8±55.6 mg GAE kg-1, HTC of 143.8±9.3 mg TAE kg-1, TFC of 17.5±1.3 mg CAE kg-1, antioxidant activity (IC50) of 56.96 ppm, ash content of 4.0±0.7%, pH value of 5.0±0.8, and yield of 9.3±0.8%. There was a strong correlation between TPC, HTC, TFC, and the antioxidant activity. Conclusions: Drying temperature affected all observed parameters but not ash and pH. Temperature of 45°C emerged as the best treatment to produce mandai powder from L. casei-inoculated mandai cempedak fermentation. The antioxidant activity of mandai cempedak was contributed by the phenolic components.


2020 ◽  
Vol 38 (No. 3) ◽  
pp. 158-163
Author(s):  
Tomasz Sawicki ◽  
Natalia Bączek ◽  
Małgorzata Starowicz

The aim of this study was to compare total phenolic and flavonoid content, antioxidant and reducing activity, as well as vitamin C and E content in beebread and honey. The antioxidant activity of samples was determined by photochemiluminescence (PCL) assay, while reducing potential was measured using FRAP and ORAC assays. Vitamin C was analysed by HPLC–MS-TripleTOF method and vitamin E by HPLC-DAD. Beebread was characterised by the higher level of the total phenolic (~90%), flavonoid (~97%), vitamin C (~99%) and E (~98%) as compared to the honey. The data showed that beebread had also higher values of antioxidant activity and reducing potential by ~99% and ~41–98%, respectively, than honey. Our findings indicate that beebread is valuable source of bioactive substances, with the high beneficial properties.


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