Ultrasound assisted osmotic dehydration of organic cranberries (Vaccinium oxycoccus): Study on quality parameters evolution during storage

Abstract

a b s t r a c tCranberries are appreciated for their high amount of antioxidants such as flavonoids, anthocyanins, phenolic acids, carotenoids and vitamins. However, due to their sour and tart taste they request to be processed into sweeter dried fruits in order to be acceptable for the consumers. The aim of this work was to analyse the effect of ultrasound assisted osmotic dehydration on mass transfer parameters and on quality characteristics during storage of cranberries. Ultrasound treatment was performed at the frequency of 21 kHz for 30 min in three osmotic solutions -61.5% sucrose, 30% sucrose with an addition of 0.1% of steviol glycosides and 40% trehalose on cut in half cranberries. Afterwards, the cranberry samples were subjected to osmotic dehydration process at 40 C for 72 h. The osmodehydrated samples both with or without ultrasound pre-treatment were collected and stored at 10 C in climatic chamber in microperforated plastic bags (PLA) for 8 weeks. The weight reduction, dry matter, water activity, colour, and microbiological analysis were performed after 1, 2, 4 and 8 weeks of storage. The obtained results indicated that ultrasound application significantly affected the mass transfer parameters during osmotic treatment, as well as it did the type of osmotic solution used. Thermal analysis showed variations in sugar melting temperature and enthalpy as a result of osmotic treatment and storage. During the storage, lower weight loss and higher lightness were observed in US pre-treated samples. The sample that preserved the best chemico-physical and microbiological characteristics during storage was the one treated with 61.5% sucrose solution, due to its lowest water activity.

High Fibre Gluten-Free Fresh Pasta with Tiger Nut, Chickpea and Fenugreek: Technofunctional, Sensory and Nutritional Properties

“…This was evidenced by the increasing colour differences values (∆E* 1 ). Generally, a visible difference between samples is considered for ∆E values above 2 [39], so these colour differences were high enough to be appreciated when over 5% (w/w) FF was included, as the sensory evaluation confirmed. These tones can be attributed to the content of carotenoids and other pigments of FF [40].…”

The Application of Combined Pre-Treatment with Utilization of Sonication and Reduced Pressure to Accelerate the Osmotic Dehydration Process and Modify the Selected Properties of Cranberries

“…The highest WL after 72 h of OD was noted after combined pretreatment with blanching and triplicate lowering of the pressure (BL_3 × 10 v_s). In turn, Nowacka et al [32] reported that US applied as a pretreatment before OD increases the WL during OD, irrespective of the osmotic solution.…”

“…However, a solution with the addition of steviol glycosides was used to reduce sugar content in dehydrated fruits. Due to the fact that steviol glycosides are up to 300 times sweeter than sucrose, the addition of little amount (0.1%) of this sweetener is enough to maintain its sweetness comparable with fruits dehydrated in a standard solution [25,32].…”

Modeling of Osmotic Dehydration of Apples in Sugar Alcohols and Dihydroxyacetone (DHA) Solutions

“…To compare the process kinetics, 50% sucrose solution was used in the experiment. Osmotic dehydration was carried out in the range from 30 to 180 min (the optimal process conditions—time and concentration—were selected for testing based on preliminary experiments in a previous work published by Cichowska et al [10]) at a temperature of 40 °C (atmospheric pressure) in ratio of 1:4 (fruit: solution) [23,24]. The mass of a single sample was 20 g ± 2 g. Afterwards, the samples were removed from the osmotic solution and blotted with absorbent paper to remove osmotic liquid from their surface.…”