Ultrasound‐assisted Osmotic Dehydration of Cranberries: Effect of Finish Drying Methods and Ultrasonic Frequency on Textural Properties

Abstract

In this study, the effect of osmotic pretreatments (with or without ultrasound) in combination with hot‐air or microwave‐assisted hot‐air drying methods on the texture, microstructure, color and water activity of dried cranberries were investigated. Osmotic pretreatments were done in a ternary solution (sucrose–NaCl–water) under three different temperatures: 30, 40 and 50C. The concentrations of osmotic solutions were 40, 50 and 60% of sucrose and 0, 4 and 8% of NaCl. Also, the influence of the two levels of frequency of ultrasound (35 and 130 kHz) on the quality properties was investigated. Our results showed lower hardness and water activity (aw) when higher temperature, sucrose and salt were used. Applying ultrasound reduced the hardness and aw of samples. With increasing the frequency of ultrasound, hardness (N) and aw were decreased. Microwave energy reduced drying time and can modify the structure, texture strength and color of the final product. PRACTICAL APPLICATIONS Cranberry contains high levels of phytochemicals, which have health‐promoting properties. Some of these phytochemicals, such as anthocyanins, act as an antioxidant, reducing the oxidative damage to cells, which can lead to cancer, heart disease and other degenerative diseases. Recently, cranberry products have been used with the hope of preventing or treating urinary tract infections or Helicobacter pylori infections, which can lead to stomach ulcers, or to prevent dental plaque. Osmotic dehydration is a suitable way to produce shelf‐stable products or partially dehydrated foods without enduring heat damage. The osmotically dehydrated cranberries can be consumed as healthy snacks or can be suited to a wide range of food formulations, including jams or sweets.

A hybrid AHP‐TOPSIS method for prospectively modeling of ultrasound‐assisted osmotic dehydration of strawberry

“…It is probably due to higher content of solid materials and lower moisture content of the samples. These results are consistent with the reported results of Shamaei et al (). Furthermore, increase of frequency causes the formation of micro channels, raptures, and destructions in fruit tissues which soften them and decrease the amount of maximum force.…”

“…Moreover, by an increase in the frequency of ultrasonic waves, dehydration of samples increases as well. It is probable that due to destruction of tissues and formation of pores and channels in the structure of samples, more amount of water comes out of the tissues (Garcia‐Noguera et al, ; Shamaei, Emam‐Djomeh, & Moini, ). More solid compounds are absorbed into the tissues by decreasing moisture content of the samples, which causes higher absorption of solid materials.…”

Effects of Various Nonthermal Pretreatments on the Physicochemical Properties of Dried Ginger (Zingiber officinaleRoscoe) Slices from Two Geographical Locations

“…It reduces the moisture content, delays decay, and lessens drying duration leading to enhancement of quality (An et al., ; Wang et al., ). However, conventional drying has been established to have a negative influence on the quality of the finished products (that is, dried ginger) as whole and on the functional and nutritional compounds in particular (Oladejo, Ma, Qu, Zhou, & Wu, ; Shamaei, Emam‐Djomeh, & Moini, ). Hence, due to the perishability of ginger, effective alternative pretreatment methods that are capable of reducing the drying time and maintaining the quality are imperative.…”

Influence of ultrasound pretreatments on diffusion coefficients, texture and colour of osmodehydrated sweet potato (Ipomea batatas)

“…However, conventional drying has been found to have adverse effects on the qualities of dried fruit and vegetables (Fernandes et al, 2008;Shamaei et al, 2012). However, conventional drying has been found to have adverse effects on the qualities of dried fruit and vegetables (Fernandes et al, 2008;Shamaei et al, 2012).…”