The influence of freeze drying conditions on microstructural changes of food products

Oikonomopoulou, Vasiliki; Krokida, Magdalini; Karathanos, Vaios Τ.

doi:10.1016/j.profoo.2011.09.097

Cited by 83 publications

(48 citation statements)

References 7 publications

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“…Freeze-drying (FD) was shown to preserve the original larval morphology of the best resulting in similar length and diameter distributions in comparison to the untreated raw larvae. This is a known behaviour as freeze-drying prevents undesirable shrinkage and produces dried goods with high porosity in comparison to conventional thermal drying [46]. Application of oven and fluidized bed drying, respectively, led to shrivelled larvae exhibiting smaller length and diameter due to tissue collapse and loss of porosity [47].…”

Section: Physico-chemical Properties Of Whole Larvaementioning

confidence: 99%

Effect of pre-treatment and drying method on physico-chemical properties and dry fractionation behaviour of mealworm larvae (Tenebrio molitor L.)

Purschke

Brüggen

Scheibelberger

et al. 2017

Eur Food Res Technol

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protein (52.5-58.2%db) and fat (21.4-26.6%db) content. Highest protein recovery of max 72% was determined in the particle size fraction 500-1000 µm. Concluding, these results provide insights into physico-chemical characteristics of mealworms affected by pre-treatment and drying. The potential of dry fractionation techniques for protein enrichment and delivery of a variety of differently composed mealworm fractions was demonstrated and may provide an interesting potential to optimize water and energy consumption during insect fractionation.

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Section: Physico-chemical Properties Of Whole Larvaementioning

confidence: 99%

Effect of pre-treatment and drying method on physico-chemical properties and dry fractionation behaviour of mealworm larvae (Tenebrio molitor L.)

Purschke

Brüggen

Scheibelberger

et al. 2017

Eur Food Res Technol

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“…Among the drying methods that used in food processing industries, freeze-drying (FD) is considered one of most advanced methods for drying high value products, since it prevents undesirable shrinkage and produces materials with high porosity, good nutritional quality, superior texture, aroma, flavour and colour retention as well as better rehydration capacity (Oikonomopoulou, Krokida, & Karathanos, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…The freezing stage has great influence on the overall efficiency of the FD; the ice crystals create pores and gaps with different characteristics, which affect the heat and mass transfer rates and the sublimation (Oikonomopoulou et al, 2011). During primary stage, the temperature of frozen layer is most often at −10°C or lower at absolute pressures of about 2 mmHg or less (Liapis & Bruttini, 2006) and at the completion of primary drying, the product can still contain approximately 15-20% of unfrozen water, which is then desorbed during the secondary drying stage, usually at elevated temperature and low pressure, to finally allow the desired low moisture content to be achieved (Kasper & Friess, 2011).…”

Section: Introductionmentioning

confidence: 99%

Effect of drying methods on the physicochemical and thermal properties of Mexican plum (Spondias purpurea L.)

Muñoz-López

Urrea-García

Jiménez‐Fernández

et al. 2017

CyTA - Journal of Food

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(2018) Effect of drying methods on the physicochemical and thermal properties of Mexican plum (Spondias purpurea L.), CyTA -Journal of Food, 16:1, 127-134, DOI: 10.1080/19476337.2017 To link to this article: https://doi.org/10. 1080/19476337.2017 Plum slices (diameter 2.5 cm and thickness 0.2 cm) were dried using vertical tray-drying (VTD) and freeze-drying. Models were used to determine the thermal conductivity (k) and specific heat (C p ). In addition, water activity (a w ), colour total change (ΔE), pectin yield (y pec ) and rehydration capacity were investigated. The moisture content of tray-and freeze-dried plum was relatively significant (p < 0.05). No significant difference was found in terms of a w . There was a maximum decrease in k and C p of 90% and 91.5% during drying process, respectively. In terms of quality, ΔE showed that tray-dried samples had slight darker (browning), whereas the freeze-dried samples had a lighter colouring compared to the fresh fruit. The quality and rehydration characteristics of freeze-dried plum were higher than that of a tray-dried product; however, VTD could be appropriate for industrial production because of its advantages in lower cost and energy consumption.Efecto de los métodos de secado sobre las propiedades fisicoquímicas y térmicas de la ciruela mexicana (Spondias purpurea L.) RESUMEN Las rebanadas de ciruela (diámetro 2,5 cm y espesor 0,2 cm) fueron secadas usando el secado vertical por charolas (VTD) y la liofilización (FD). Se utilizaron modelos para determinar la conductividad térmica (k) y el calor específico (C p ). Además, la actividad de agua (a w ), el cambio total de color (ΔE), el rendimiento de pectina (y pec ) y la capacidad de rehidratación fueron investigados. El contenido de humedad de la ciruela seca y liofilizada fue relativamente significativo (p < 0,05). No se encontraron diferencias significativas en términos de a w . Hubo un máximo decremento en k y C p del 90% y 95% durante el proceso de secado, respectivamente. En términos de calidad, ΔE mostró que las muestras secadas en charolas tuvieron un ligero oscurecimiento (pardeamiento), mientras las muestras liofilizadas tuvieron un color más luminoso en comparación con la muestra fresca. La calidad y las características de rehidratación fueron mayores que las de un producto secado por charolas; sin embargo, VTD podría ser apropiado para la producción industrial debido a sus ventajas de bajo costo y consumo energético. ARTICLE HISTORY

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“…This process enables a better preservation of the characteristics of the product, maintenance of final quality and increase in food's useful life due to the reduction in the water content and consequent decrease in the moisture of the product (Sanjinez-Argandoña et al, 2011). The principle used for it is the sublimation, i.e., the change from solid state directly to the gaseous state, using vacuum and low temperature in the dehydration process (Oikonomopoulou et al, 2011). Storage in adequate packages becomes necessary in lyophilized products, for the stability during storage.…”

Section: Introductionmentioning

confidence: 99%

Stability of ‘mangaba’ pulp powder obtained by freeze drying

Conegero

Ribeiro

Costa

et al. 2017

Rev. bras. eng. agríc. ambient.

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A B S T R A C TThis work examined the stability of lyophilized 'mangaba' pulp powder, rolled and packaged in plastic containers, with and without vacuum during 90 days of storage under room temperature, with evaluation of the parameters every 15 days. Analyses of ascorbic acid concentration, pH, color and water activity were carried out. It was found that ascorbic acid remained in accordance with the standards specified for daily consumption according to the Brazilian legislation in all analyzed packages, with preservation of stability in the laminated package with vacuum, which was also effective in maintaining water activity, which contributes to better stability of the product.Estabilidade do pó da polpa de mangaba obtido por liofilização R E S U M O A conservação de produtos desidratados, como aqueles obtidos por liofilização, torna necessária a avaliação das características físico-químicas do produto durante o armazenamento. Foi analisada a estabilidade da mangaba em pó obtida por secagem, através de liofilização, acondicionada em embalagens laminadas e plásticas, com e sem vácuo, durante 90 dias de armazenamento em temperatura ambiente. A cada 15 dias de armazenamento foram realizadas as análises de concentração de ácido ascórbico, pH, atividade de água e cor. Verificou-se que o ácido ascórbico se manteve de acordo com os padrões indicados para consumo diário, conforme a legislação brasileira em todas as embalagens analisadas, com preservação da estabilidade pela embalagem laminada com vácuo, que também foi eficaz na manutenção da atividade de água, o que contribui para melhor estabilidade do produto.

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The influence of freeze drying conditions on microstructural changes of food products

Cited by 83 publications

References 7 publications

Effect of pre-treatment and drying method on physico-chemical properties and dry fractionation behaviour of mealworm larvae (Tenebrio molitor L.)

Effect of pre-treatment and drying method on physico-chemical properties and dry fractionation behaviour of mealworm larvae (Tenebrio molitor L.)

Effect of drying methods on the physicochemical and thermal properties of Mexican plum (Spondias purpurea L.)

Stability of ‘mangaba’ pulp powder obtained by freeze drying

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