Kinetics of Atmospheric Freeze-drying of Apple

Stawczyk, J.; Li, Sheng; Witrowa‐Rajchert, Dorota; Fabisiak, Anna

doi:10.1007/s11242-006-9012-4

Cited by 26 publications

(20 citation statements)

References 3 publications

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“…In LTD, no thermal damage could be expected in the antioxidant compounds due to the fact that dehydration occurs at very low temperatures. In this sense, Stawczyk et al [33] found an average reduction in the polyphenol content of 20% in the convective drying of apple cubes, pre-treated in a 3% citric acid solution (1 cm side) at -8 and -12ºC.…”

Section: Antioxidant Potentialmentioning

confidence: 99%

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Impact of applied ultrasonic power on the low temperature drying of apple

Santacatalina

Contreras

Simal

et al. 2016

Ultrasonics Sonochemistry

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Low temperature drying (LTD) allows high-quality dried products to be obtained, preserving the nutritional properties of fresh foods better than conventional drying, but it is a time-consuming operation. Power ultrasound (US) could be used to intensify LTD, but it should be taken into account that process variables, such as the level of applied power, have an influence on the magnitude and extension of the ultrasonic effects. Therefore, the aim of this work was to assess the influence of the level of applied ultrasonic power on the LTD of apple, analyzing the drying kinetics and the quality of the dried product. For that purpose, apple (Malus domestica cv. Granny Smith) cubes (8.8mm side) were dried (2m/s) at two different temperatures (10 and -10°C), without and with (25, 50 and 75 W) US application. In the dried apple, the rehydration kinetics, hardness, total phenolic content, antioxidant capacity and microstructure were analyzed to evaluate the impact of the level of applied ultrasonic power. At both temperatures, 10 and -10°C, the higher the ultrasonic power level, the shorter the drying time; the maximum shortening of the drying time achieved was 80.3% (at -10°C and 75 W). The ultrasonic power level did not significantly (p<0.05) affect the quality parameters analyzed. Therefore, US could be considered a non-thermal method of intensifying the LTD of fruits, like apple, with only a mild impact on the quality of the dried product.

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Section: Antioxidant Potentialmentioning

confidence: 99%

“…These results could be explained by the highly porous structure caused by the water sublimation at -10ºC, due to the fact that the sample shrinkage is almost negligible [33].…”

Section: Rehydration Experimentsmentioning

confidence: 99%

Impact of applied ultrasonic power on the low temperature drying of apple

Santacatalina

Contreras

Simal

et al. 2016

Ultrasonics Sonochemistry

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“…Apple cubes [131] To design and build a heat pump-assisted, packed bed AFD closed system and investigate the drying kinetics effect on the quality (rehydration kinetics, shrinkage, color, and antioxidant activity) of apple cubes…”

Section: Plant-based Food Objectives Conclusionmentioning

confidence: 99%

Freeze-Drying of Plant-Based Foods

Bhatta

Janežić

Ratti

2020

Foods

230

103

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Vacuum freeze-drying of biological materials is one of the best methods of water removal, with final products of highest quality. The solid state of water during freeze-drying protects the primary structure and the shape of the products with minimal volume reduction. In addition, the lower temperatures in the process allow maximal nutrient and bioactive compound retention. This technique has been successfully applied to diverse biological materials, such as meats, coffee, juices, dairy products, cells, and bacteria, and is standard practice for penicillin, hormones, blood plasma, vitamin preparations, etc. Despite its many advantages, having four to ten times more energy requirements than regular hot air drying, freeze-drying has always been recognized as the most expensive process for manufacturing a dehydrated product. The application of the freeze-drying process to plant-based foods has been traditionally dedicated to the production of space shuttle goods, military or extreme-sport foodstuffs, and specialty foods such as coffee or spices. Recently, the market for ‘natural’ and ‘organic’ products is, however, strongly growing as well as the consumer’s demand for foods with minimal processing and high quality. From this perspective, the market for freeze-dried plant-based foods is not only increasing but also diversifying. Freeze-dried fruits and vegetables chunks, pieces, or slices are nowadays majorly used in a wide range of food products such as confectionaries, morning cereals, soups, bakeries, meal boxes, etc. Instant drinks are prepared out of freeze-dried tea, coffee, or even from maple syrup enriched with polyphenol concentrated extracts from trees. The possibilities are endless. In this review, the application of freeze-drying to transform plant-based foods was analyzed, based on the recent research publications on the subject and personal unpublished data. The review is structured around the following related topics: latest applications of freeze-drying to plant-based foods, specific technological problems that could be found when freeze-drying such products (i.e., presence of cuticle; high sugar or lipid concentration), pretreatments and intensification technologies employed in freeze-drying of plant-based foods, and quality issues of these freeze-dried products.

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“…These results could be 298 explained by the fact that drying at -10ºC leads to a minimum shrinkage and a highly 299 porous structure (Stawczyk, Li, Witrowa-Rajchert, and Fabisiak, 2007). So, the high 300 porosity makes it easier for water to enter the dried matrix.…”

mentioning

confidence: 99%

Ultrasonically assisted low-temperature drying of desalted codfish

Santacatalina

Guerrero

García-Pérez

et al. 2016

LWT

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28The application of US increased the drying rate at every temperature tested, 29 shortening the drying time by 16% at 0ºC and up to 60% at -10ºC. The ultrasonically 30 assisted dried samples presented a rehydration rate which was slightly lower than that 31 of those that had been conventionally dried, but they were harder and whiter, which is 32 more suited to consumer preferences. Therefore, power ultrasound could be 33 considered an affordable technology with which to accelerate LTD of desalted cod, 34 providing high quality dried products. 35 36

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Kinetics of Atmospheric Freeze-drying of Apple

Cited by 26 publications

References 3 publications

Impact of applied ultrasonic power on the low temperature drying of apple

Impact of applied ultrasonic power on the low temperature drying of apple

Freeze-Drying of Plant-Based Foods

Ultrasonically assisted low-temperature drying of desalted codfish

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