Glass transition changes during osmotic dehydration

Rosas-Mendoza, Marta E.; Fernández-Muñoz, J. L.; Arjona‐Román, José Luis

doi:10.1016/j.profoo.2011.09.123

Cited by 6 publications

(6 citation statements)

References 19 publications

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“…Therefore, crystalline sucrose would not be contributing to increased T g , and the available water would be plasticizing the remaining amorphous phase, leading to low T g values. This behavior was also observed in several studies performed on fruits, showing that pretreated samples presented lower T g values than control ones: air-and freeze-dried tomato (Telis and Sobral, 2001); air-dried apple (Del Valle et al, 1998;Sosa et al, 2012); freezedried apple (Sá et al, 1999;Sosa et al, 2012); and air-dried mango (Rosas-Mendoza et al, 2011). 1 H NMR relaxation times (t 2 ) were determined at 20 °C by a single 90° pulse, as an estimation of molecular mobility.…”

Section: Physical Propertiessupporting

confidence: 70%

Physical and mechanical properties of raspberries subjected to osmotic dehydration and further dehydration by air- and freeze-drying

Sette

Salvatori

Schebor

2016

Food and Bioproducts Processing

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The aim of this study was to analyze the effect of the application of dry and wet sucrose infusions, as pretreatments previous to air-and freeze-drying, on mechanical and physical properties of raspberries: water sorption, glass transition temperature (T g), molecular mobility, texture and rehydration properties. Different dry and wet sugar infusions were prepared using combinations of additives: sodium bisulphite, citric acid, sodium bisulphite and citric acid, and no additives. These specific pretreatments are often used to obtain better sensorial characteristics of fruits upon further drying. After the dehydration step (air-or freeze-drying), all the samples were in the supercooled state. Pretreated samples presented lower T g values and lower spin-spin relaxation times than control samples. Regarding texture, pretreated samples showed lower firmness than control samples. Also, freeze-dried pretreated samples showed higher firmness and lower deformability than air-dried pretreated ones. When considering the hygroscopicity, freeze-dried samples were more hygroscopic than air-dried ones. The fresh-like dried raspberries obtained could be directly consumed as snacks or incorporated in a composite food, such as a cereal mix. In this latter case, pretreated fruits would be more suitable, since their rehydration capacity at short times was relatively low.

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Section: Physical Propertiessupporting

confidence: 70%

Physical and mechanical properties of raspberries subjected to osmotic dehydration and further dehydration by air- and freeze-drying

Sette

Salvatori

Schebor

2016

Food and Bioproducts Processing

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“…This transition is more pronounced for systems of low‐molecular weight, including our fruit pulp samples. Similar shapes of the water vapor sorption isotherms characterize other fruits, such as kiwis and grapes (Roos, 1987), pineapples (Telis & Sobral, 2001), strawberry (Moraga et al, 2006), or mangoes (Rosas‐Mendoza et al, 2011; Zhao et al, 2015). The mango sample showed a different behavior, with a sorption isotherm closer to Type II (Timmermann et al, 2001).…”

Section: Resultsmentioning

confidence: 80%

State diagrams and water sorption isotherms of pitanga, ciriguela araza, mango, and guava

Sviech

Cardoso

Oliveira

et al. 2023

J Food Process Engineering

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State diagrams for araza, ciriguela, guava, mango, and pitanga were built as a function of concentration and temperature. These state diagrams include the dependence of the glass transition temperature (Tg) on the water content, the glass transition temperature (Tg′) and concentration (Cg′) of the maximally freeze‐concentrated state and the ice melting (Tm) line. Tg′ was determined to be −57.6 to −48.94°C and Cg′ was determined to be 70 and 83% wt/wt for pitanga and ciriguela, respectively. The Tg and Tm lines were fitted with the Gordon–Taylor and Chen models, respectively. Correlations between the phase and state transitions and composition of the fruit samples were obtained. Water vapor sorption isotherms were determined, which, in combination with the state diagram, allow determining optimal processing and storage conditions for the five fruits. Practical Applications This paper presents the state diagrams and water vapor sorption isotherms for five fruits as tools for determining optimal processing and storage conditions. In this way, it is possible to establish which conditions of temperature and humidity of the process are the most suitable for the fruit storage or processing ensuring product quality and security.

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“…Likewise, a change in temperature and/or moisture content within samples' structure that occurs during OD pretreatment process leads to a change of glass transition temperature ( T g′) of products (Lowithun & Charoenrein, 2009; Rosas‐mendoza, Fernandez‐Munoz, & Arjona‐Román, 2011; Zhao et al, 2018). The modification of rambutan (Lowithun & Charoenrein, 2009) and mango (Rosas‐mendoza et al, 2011) by osmotic syrups confirms that osmotic agents can raise the T g′ of plant tissue. For instance, the T g′ values of untreated and treated rambutan (in maltitol, sucrose, and trehalose solution) are −48.6, −47.4, −46.7, and −42.1°C, respectively (Lowithun & Charoenrein, 2009).…”

Section: Effects Of Osmotic Dehydration Pretreatment On Freezing Char...mentioning

confidence: 99%

“…shows a reduction in enthalpy values during osmotic dehydration process of tomato Tocci and Mascheroni (2008). reported that the osmotic dehydration process (in sucrose solution) reduces the values of enthalpy, heat capacity, and the initial freezing temperature of kiwifruit.Likewise, a change in temperature and/or moisture content within samples' structure that occurs during OD pretreatment process leads to a change of glass transition temperature (Tg 0 ) of products(Lowithun & Charoenrein, 2009;Rosas-mendoza, Fernandez-Munoz, & Arjona- Román, 2011;Zhao et al, 2018). The modification of rambutan(Lowithun & Charoenrein, 2009) and mango(Rosas-mendoza et al, 2011) by osmotic syrups confirms that osmotic agents can raise the Tg 0 of plant tissue.…”

mentioning

confidence: 92%

“…reported that the osmotic dehydration process (in sucrose solution) reduces the values of enthalpy, heat capacity, and the initial freezing temperature of kiwifruit.Likewise, a change in temperature and/or moisture content within samples' structure that occurs during OD pretreatment process leads to a change of glass transition temperature (Tg 0 ) of products(Lowithun & Charoenrein, 2009;Rosas-mendoza, Fernandez-Munoz, & Arjona- Román, 2011;Zhao et al, 2018). The modification of rambutan(Lowithun & Charoenrein, 2009) and mango(Rosas-mendoza et al, 2011) by osmotic syrups confirms that osmotic agents can raise the Tg 0 of plant tissue. For instance, the Tg 0 values of untreated and treated rambutan (in maltitol, sucrose, and trehalose solution) are À48.increase in Tg 0 provides a safe condition for glassy state storage because solid mass movement occurs at a very slow rate and causes minimal physical and chemical changes in tissues of fruits and vegetables(Mahato, Zhu, & Sun, 2019; Bunger et al (2004).…”

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confidence: 92%

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Effects of osmotic dehydration pretreatment on freezing characteristics and quality of frozen fruits and vegetables

Alabi

Olalusi

Olaniyan

et al. 2022

J Food Process Engineering

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Osmotic dehydration (OD) is a process of soaking products in an aqueous solution containing salt or sugar, which is normally applied to fruits and vegetables. The combination of OD pretreatment with freezing, or osmotic dehydrofreezing (ODF), is a novel technology to shorten the freezing process and prolong the preservation of fruits and vegetables. However, the effectiveness of ODF is affected by process parameters and nature of the product, thus information on freezing characteristics and quality of osmotically dehydrated frozen fruits and vegetables is useful to the food industry. This review intends to provide an overview of the effects of OD pretreatment on freezing characteristics such as freezing rate, thermal properties, and quality of frozen fruits and vegetables. Fundamentals of ODF technology, including significance of OD to freezing, and mechanism and factors affecting ODF are summarized. In addition, hurdle technologies comprising of ODF and other innovative nonthermal techniques, such as ultrasound and pulsed electric field (PEF) are presented, and future trends of the combined technology are briefly discussed. ODF can accelerate the freezing process and enhance the quality of osmotically dehydrated frozen fruits and vegetables. The novel ultrasound and PEF techniques, which can provide cryoprotection from in situ interference, were proposed for the production of product with many‐functional characteristics, by incorporating bioactive compounds like plants sterols, probiotics, and dietary fibers, into the matrix of cellular tissues during ODF process. However, these techniques can enhance the performance of the ODF to promote fast freezing, produce small ice crystals, and raise glass transition temperature of cellular tissues. The future trends of ODF technology should mainly focus on controlling the mass and heat transfer processes, improving quality stability during glassy state storage condition and development of product with many‐functional characteristics. Practical Applications Fruits and vegetables are subject to freezing damage, particularly tissue softening and drip loss when thawing, thus reducing their quality and market value. OD pretreatments to freezing or ODF has great potentials in preservation of fruits and vegetables, with the advantage of minimum quality loss due to the reduction in freezing loads. Currently, innovative studies have been carried out on the combined use of OD pretreatments and emerging freezing techniques to improve the freezing process, achieve better quality with extended shelf life, and produce products with many‐functional characteristics. However, the findings presented in this review work can provide detail insights on the quality of fruits and vegetables that were frozen by ODF and give some guidance for further developments of ODF technology.

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Glass transition changes during osmotic dehydration

Cited by 6 publications

References 19 publications

Physical and mechanical properties of raspberries subjected to osmotic dehydration and further dehydration by air- and freeze-drying

Physical and mechanical properties of raspberries subjected to osmotic dehydration and further dehydration by air- and freeze-drying

State diagrams and water sorption isotherms of pitanga, ciriguela araza, mango, and guava

Effects of osmotic dehydration pretreatment on freezing characteristics and quality of frozen fruits and vegetables

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