Experimental study of dehydration processes of raspberries (Rubus Idaeus ) with microwave and solar drying

Rodríguez, Anabel; Bruno, Estela; Paola, C. A.; Campañone, Laura Analía; Mascheroni, Rodolfo Horacio

doi:10.1590/fst.29117

Cited by 20 publications

(16 citation statements)

References 32 publications

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“…The color of the fruit is one of the key sensory quality parameters because it affects the acceptability of consumers (Rodriguez et al, 2019;Si et al, 2016). The a* value of the dried samples changed from 9.03 to 31.…”

Section: Color and Surface Characteristicsmentioning

confidence: 99%

Ultrasound‐assisted vacuum drying as alternative drying method to increase drying rate and bioactive compounds retention of raspberry

Tekin-Çakmak

Cakmakoglu

Avcı

et al. 2021

J. Food Process. Preserv.

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This study aimed to determine the effect of different drying methods, namely hot air drying (HAD), vacuum drying (VD), ultrasound-assisted vacuum drying (USVD), and freeze drying (FD) on drying kinetic, total phenolic antioxidant activity, anthocyanin profile, in vitro-bioaccessibility of phenolic and color quality of raspberry samples. The drying time of the raspberry was 540, 720, and 1,140 min for USVD, VD, and HAD, respectively, indicating that USVD showed a significantly lower drying time than VD and HAD. The results of anthocyanin profile, TPC, CUPRAC, and DPPH analysis showed that FD had higher bioactive compound retention than other methods, followed by USVD. Cyanidin 3-O-sophoroside and Cyanidin 3-O-glucoside were found as the most abundant anthocyanin in raspberry samples. In the content of cyanidin 3-O-sophoroside, a loss of 78.33%, 15.41%, and 4.63% was observed in HAD, VD, and USVD, respectively. In vitro bioaccessibility of the VD and USVD were higher than FD and HAD. While the recovery value of TPC (%) was found for fresh raspberry as 3.09%, it was found as 6.79, 9.42, 8.46, and 5.58% for HAD, VD, USVD, and FD, respectively. Color quality was significantly affected by drying methods (p < .05), and USVD showed the lowest ∆E value. SEM analysis showed that less shrinkage and cell damage were observed in FD-and USVD-dried samples. This study suggested that USVD could be used as an alternative drying method since it showed lower drying time and shrinkage, higher bioactive compounds, and color retention than VD and HAD.Practical application: Raspberry is a popularly consumed fruit rich in bioactive compounds such as anthocyanin and vitamin C. Raspberry is a fruit with a low shelf life, sensitive to microorganisms and enzyme activities due to its high nutritional content and water activity. Drying is one of the most widely used methods to increase the shelf life of raspberries. It is crucial to find a suitable drying method because the bioactive components, color, and physical structure may change during drying. In this study, the effects of four drying methods on the total bioactive components, anthocyanin profile, microstructural structure, color, and phenolic antioxidant in vitro bioaccessibility of raspberry fruit were investigated. The study contains original data.

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Section: Color and Surface Characteristicsmentioning

confidence: 99%

Ultrasound‐assisted vacuum drying as alternative drying method to increase drying rate and bioactive compounds retention of raspberry

Tekin-Çakmak

Cakmakoglu

Avcı

et al. 2021

J. Food Process. Preserv.

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“…At their full maturity, raspberries have high moisture content (84% w.b. ), L-ascorbic acid content, and potassium, as well as proteins, fibers, and minerals [3,4,5,6,7]; moreover, they contain various biologically active compounds (BACs) with high antioxidant activity. BACs found in raspberries include anthocyanins (cyanidin-3-sambubioside, cyanidin-3-glucoside, cyanidin-3-xylosylrutinoside, and cyanidin-3-rutinoside), ellagic acid, hydrolysable tannins (derivatives of gallic and ellagic acid), proanthocyanidins, vecetin, quercetin and rutin [8,9,10], carotenoids (lutein, zeaxanthin, alpha carotene, and beta carotene), chlorophyll derivatives, and tocopherols [11], with antioxidative and anti-inflammatory potential [12,13].…”

Section: Introductionmentioning

confidence: 99%

Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties

Stamenković

Pavkov

Radojčin

et al. 2019

Foods

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Raspberries are one of Serbia’s best-known and most widely exported fruits. Due to market fluctuation, producers are looking for ways to preserve this fresh product. Drying is a widely accepted method for preserving berries, as is the case with freeze-drying. Hence, the aim was to evaluate convective drying as an alternative to freeze-drying due to better accessibility, simplicity, and cost-effectiveness of Polana raspberries and compare it to a freeze-drying. Three factors were in experimental design: air temperature (60, 70, and 80 °C), air velocity (0,5 and 1,5 m · s−1), and state of a product (fresh and frozen). Success of drying was evaluated with several quality criteria: shrinkage (change of volume), color change, shape, content of L-ascorbic acid, total phenolic content, flavonoid content, anthocyanin content, and antioxidant activity. A considerable influence of convective drying on color changes was not observed, as ΔE was low for all samples. It was obvious that fresh raspberries had less physical changes than frozen ones. On average, convective drying reduced L–ascorbic acid content by 80.00–99.99%, but less than 60% for other biologically active compounds as compared to fresh raspberries. Convective dried Polana raspberry may be considered as a viable replacement for freeze-dried raspberries.

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“…Data recording started when the plunger got into contact with sample surface and achieved a trigger force of 0.5 N. The force-distance curve was recorded during the test until the force of 100 N. The first peak force that caused breaking of the sample reflected the mechanical resistance of the sample, that is, its hardness. 4,39,40 Shear force resistance was tested with a 1-mm-thick knife blade, and the same speed of the blade was applied as a trigger force for hardness determination test. The force-distance curve was recorded until displacement of 30 mm was reached upon the application of the trigger force.…”

Section: Physical and Mechanical Propertiesmentioning

confidence: 99%

“…Red raspberry is a commonly consumed fruit for its aromatic flavor and as addition to other products to provide essential nutrients for human health. 1,2 Raspberry is considered a good source of L-ascorbic acid, ellagic acid, and potassium as well as the proteins, fibers, minerals, 1,[3][4][5][6] and various biologically active compounds with high antioxidant activity. [7][8][9][10][11] Mullen and coworkers found eight anthocyanins in red raspberry: cyanidin-3-sophoroside, cyanidin-3-(2-glucosylrutinoside), cyanidin-3-glucoside, pelargonidin-3-sophoroside, cyanidin-3-rutinoside, pelargonidin-3-(2-glucosylrutinoside), pelargonidin-3-glucoside, and pelargonidin-3-rutinoside).…”

Section: Introductionmentioning

confidence: 99%

Ranking and multicriteria decision making in optimization of raspberry convective drying processes

Stamenković

Radojčin

Pavkov

et al. 2020

Journal of Chemometrics

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Serbia is one of the leading producers and exporters of raspberry in the world, and considering the short shelf life of raspberry, the processing, storage, and transport are some of the main issues to be addressed. A comparative experiment was conducted in order to find the suitable process parameters for convective drying that may be considered as the alternatives to freeze‐drying, which is a widely used preservation method for raspberry even though it is a costly and energy‐consuming method. Twelve convective drying regimens were applied with a combination of three influencing factors: air temperature (60°C, 70°C, and 80°C), air rate (0.5 and 1.5 m·s−1), and stage of raspberry (fresh and frozen). The final product, a dried raspberry, was assessed for chemical, physical, and mechanical properties and rehydration capacity. Deep ranking analysis by power eigenvectors (DRAPE) and sum of ranking differences (SRD) were used to uncover the differences and similarities between the applied drying methods. SRD showed that convective drying of fresh raspberries proved to be more similar to freeze‐dried raspberries than convective drying of frozen ones. Fresh samples dried at 60 °C air temperature and 1.5 m·s−1 air flow proved to be the most similar to the reference freeze‐drying method. This convective regimen gives samples with the lowest color change, shrinkage, and shape deformation. With the mechanical and chemical properties of these samples being observed, statistical Duncan's test show that there is no significant difference (P < .05) in terms of hardness, shear force resistance, total phenolic, and total flavonoid preservation, compared with freeze‐dried samples. DRAPE gave similar results, but it added the variable importance in ranking as well, and total phenol reduction was defined as the most important variable. These results can help practitioners to develop cheaper and simpler drying methods that would replace the freeze‐drying but keep the same quality of the dried products.

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Experimental study of dehydration processes of raspberries (Rubus Idaeus ) with microwave and solar drying

Cited by 20 publications

References 32 publications

Ultrasound‐assisted vacuum drying as alternative drying method to increase drying rate and bioactive compounds retention of raspberry

Ultrasound‐assisted vacuum drying as alternative drying method to increase drying rate and bioactive compounds retention of raspberry

Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties

Ranking and multicriteria decision making in optimization of raspberry convective drying processes

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