Freeze-drying: The Basic Process

García-Amezquita, Luis Eduardo; Welti‐Chanes, Jorge; Vergara-Balderas, F.; Bermúdez‐Aguirre, Daniela

doi:10.1016/b978-0-12-384947-2.00328-7

Cited by 19 publications

(16 citation statements)

References 3 publications

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“…e food industry prefers FD over HA because the thermal damage of heatsensible compounds in foods is avoided, preserving some sensory and structural characteristics. However, FD is an expensive process mainly because of the large energy consumption to maintain the sublimation conditions [18]. Besides, the changes produced in the cell wall during the freezing stage could modify the properties of the fibre powders.…”

Section: Introductionmentioning

confidence: 99%

Influence of Drying Method on the Composition, Physicochemical Properties, and Prebiotic Potential of Dietary Fibre Concentrates from Fruit Peels

García-Amezquita

Tejada-Ortigoza

Campanella

et al. 2018

Journal of Food Quality

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Dietary fibre concentrates (DFC) obtained from fruit and vegetable by-products are powders, mainly obtained by dehydration, used in food formulations to increase nutritional value and to improve functional properties. The modifications of insoluble, soluble, and total dietary fibres (IDF, SDF, and TDF), physicochemical properties (solubility, swelling capacity, water/oil retention capacity, pH, and tapping density), and prebiotic potential of DFC from orange, mango, and prickly pear peels obtained by freeze-drying (FD) and convective hot air-drying (HA) were studied. In vitro faecal fermentation was used to evaluate the short-chain fatty acid (SCFA) production as a prebiotic indicator. TDF in FD orange was 5.5 g·100 g−1 higher than that in the HA sample, whereas HA increased TDF in prickly pear (9.5 g·100 g−1). No differences in fibre composition were observed in mango DFC. The physicochemical properties mostly affected by dehydration treatment were solubility and swelling capacity. HA increased SCFA production in orange peel (48 mmol·g−1 higher) but decreased it in mango and prickly pear (15 and 19 mmol·g−1 lower). Butyrate production of HA orange DFC was comparable to that obtained with the positive control (4.5 mmol·g−1). No production of propionate or butyrate was observed after 6 h fermentation in mango samples, despite the high SDF content (≈20 g·100 g−1). A decrease of the SDF : TDF ratio produced by the drying method improved the SCFA production.

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Section: Introductionmentioning

confidence: 99%

Influence of Drying Method on the Composition, Physicochemical Properties, and Prebiotic Potential of Dietary Fibre Concentrates from Fruit Peels

García-Amezquita

Tejada-Ortigoza

Campanella

et al. 2018

Journal of Food Quality

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“…It is well known that the freeze‐drying method is the best technique to dehydrate foods with the best preservation of functional ingredients in foods (Garcia‐Amezquita, Welti‐Chanes, Vergara‐Balderas, & Bermúdez‐Aguirre, 2016), because many functional compounds, including phenolic compounds and antioxidants, are susceptible to oxidation, which results in a loss of their bioactive functions (Joshi, Rupasinghe, & Khanizadeh, 2011). During the freeze‐drying process, low temperature condition with the absence of oxygen could better prevent these functional elements from being oxidized (Shahdadi, Mirzaei, & Daraei Garmakhany, 2015; Shahdadi, Mirzaei, Maghsoudlou, Ghorbani, & Daraei, 2011).…”

Section: Resultsmentioning

confidence: 99%

Effect of different drying methods on phenolic compounds and antioxidant capacity in different fractions of Sedum aizoon L.

Gong

Qiu

Weng

et al. 2020

J Food Process Preserv

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This study investigated the effect of different drying treatments on phenolic composition and antioxidant activity in different fractions of Sedum aizoon L. Results showed that the highest flavonoids content was found in the flower fraction, which also possessed the strongest antioxidant capacity confirmed by DPPH, ABTS, and FRAP assays. Four phenolic compounds were detected in Sedum aizoon L. Myricetrin and quercitrin were the dominant phenolic compounds in all the fractions, whereas the stem fraction did not contain myricetin. Among the drying treatments, each freeze‐dried fraction exhibited the highest antioxidant activities and total flavonoids. The oven‐ and sun‐drying treatments resulted in a loss on the total flavonoids and antioxidant properties. A positive correlation of antioxidant activities in Sedum aizoon L. was found with myricetrin, quercitrin and total flavonoids. This study could provide useful information on the nutritional quality improvement of Sedum aizoon L. through different drying methods. Practical applications Sedum aizoon L. has been generally consumed as a folk medicine with multiple health beneficial features in China. The health beneficial properties of Sedum aizoon L. have been confirmed to be attributed primarily to phytochemicals, such as flavonoids and phenolic acids. The major consumption parts in Sedum aizoon L. in China include stems, leaves, and flowers. Normally, a drying process has been applied to Sedum aizoon L. for a longer shelf life need. The present study investigated the distribution of gallic acid, myricetrin, quercitrin, and myricetin in different parts of Sedum aizoon L., and further assessed if different drying methods could alter the level of these phenolic compounds and antioxidant properties in these parts of Sedum aizoon L. This study provides direct knowledge on the accumulation of phenolic compounds in different parts of Sedum aizoon L., and further bring a practical method on the best preserve functional compounds in Sedum aizoon L.

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“…The second stage is drying to remove the ice through sublimation, which is done by reducing the pressure of the system while maintains the system temperature. The final step is called secondary drying, in which bound water is removed until the residual moisture (Garcia-Amezquita et al, 2016). Several works indicate that protein denaturation during the formation of ice crystals can be a relevant factor changing the protein structure (Garcia-Amezquita et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…The final step is called secondary drying, in which bound water is removed until the residual moisture (Garcia-Amezquita et al, 2016). Several works indicate that protein denaturation during the formation of ice crystals can be a relevant factor changing the protein structure (Garcia-Amezquita et al, 2016). Optimization of the freezing process should therefore take the effect of the ice surface area into account since it can contribute to freeze-induced protein denaturation.…”

Section: Introductionmentioning

confidence: 99%

Dehydration of protein lactoferrin-glycomacropeptide nanohydrogels

et al. 2020

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A B S T R A C TProtein based nanohydrogels have recently gained interest due their high ability to carry and deliver active compounds. However, one of the limitations of using protein-based systems is their high sensitivity to physicochemical stresses during processing and storage. Protein-based formulations are commonly prepared as solid dosage forms once their stability can be achieved in the solid rather than in the liquid state. One of the methods to improve the stability of protein-based systems is drying, being freeze and spray drying the most popular methods. Nanohydrogels composed of lactoferrin and glycomacropeptide were developed by thermal gelation and dried using a freeze-dryer (CHRIST -Alpha 1-4 LD plus, Germany) and a nano spray dryer B-90 (BÜCHI Labortechnik AG, Switzerland). For nano spray-drying different experimental conditions were tested such as: the inlet temperature (80, 100 and 120 � C) and the hole size of the vibrating membrane in the spray cap (4 μm and 7 μm), while for freeze drying the nanohydrogels where maintained at À 40 � C for a drying period of about 24 h. The physicochemical properties of the resulting dried nanohydrogels were compared through different techniques: differential scanning calorimetry (DSC), thermogravimetry (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). DSC shows an endothermic peak ranging from 82 to 90 � C, indicating that during the drying methodologies the second denaturation peak of lactoferrin (around 90 � C) is maintained. No significant differences (p < 0.05) for denaturation peak temperatures were observed when different inlet temperatures or spray cap size were applied during the nano spray-drying conditions. When compared with freeze-drying it is possible to observe that a denaturation peak around the same range of temperatures was detected, also indicating that this drying process did not affect the denaturation of the protein. XRD results of nanohydrogels dried by freeze-drying revealed that crystallinity is significantly higher when compared with spray-dried nanohydrogels, explaining the lower thermal degradation observed in TGA for freeze-dried nanohydrogels. Nanohydrogels morphology after the drying process was evaluated by SEM. Nanohydrogels obtained by nano spray dryer B-90 allowed identifying the presence of particles with spherical shape, while nanohydrogels obtained by freeze drying had a sponge-like appearance. This work shows the influence of the drying process of protein-based nanohydrogels in their physical-chemical properties, thus pointing at which will be the preferred technology to be used in a future industrial application.

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Freeze-drying: The Basic Process

Cited by 19 publications

References 3 publications

Influence of Drying Method on the Composition, Physicochemical Properties, and Prebiotic Potential of Dietary Fibre Concentrates from Fruit Peels

Influence of Drying Method on the Composition, Physicochemical Properties, and Prebiotic Potential of Dietary Fibre Concentrates from Fruit Peels

Effect of different drying methods on phenolic compounds and antioxidant capacity in different fractions of Sedum aizoon L.

Dehydration of protein lactoferrin-glycomacropeptide nanohydrogels

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