INVESTIGATION OF REHYDRATION BEHAVIOR OF DIFFERENT PRODUCTS AFTER FREEZE-DRYING
5 th INTERNATIONAL SCIENTIFIC RESEARCH AND INNOVATION CONGRES, Bishkek, Kırgızistan, 29 - 30 Haziran 2026, cilt.1, sa.1, ss.819-827, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Cilt numarası: 1
- Basıldığı Şehir: Bishkek
- Basıldığı Ülke: Kırgızistan
- Sayfa Sayıları: ss.819-827
- Recep Tayyip Erdoğan Üniversitesi Adresli: Evet
Özet
Drying is a method that has been used since ancient times, enabling the long-term preservation of products by removing the moisture they contain. During the drying process, the main objective is to remove the maximum amount of moisture from the material being dried while keeping energy consumption at a minimum. By removing water from materials to be dried, microbial activity and biochemical reactions are minimized, thereby preserving aroma, nutritional value, and quality parameters and extending the product’s shelf life. Many preservation methods have been used in the past and continue to be used today, including canning, drying, fermentation, salting, seasoning, deep freezing, and sun drying. Although sun drying, one of the traditional drying methods, is low-cost, it is not preferred on an industrial scale today due to several disadvantages such as its very long drying time, the need for large areas, and hygiene concerns. In this context, the use of modern technologies such as fluidizedbed, spray, microwave, tunnel, infrared, and especially freeze drying has become widespread. Freeze drying (lyophilization) involves converting most of the moisture in a product into a solid phase and then removing the frozen water from the product structure under vacuum (low pressure). The freeze-drying process basically consists of freezing, the primary drying period (sublimation or removal of free water contained in the product), and the secondary drying period (desorption and removal of chemically bound water). Compared to other drying methods, freeze drying is a highly advantageous method because it preserves the structure of the product and results in high product quality. One of the most important quality parameters of freeze-dried products is their rehydration capacity. Rehydration refers to the ability of a dried product to return to a structure close to its fresh state and regain its original properties when it comes into contact with water. This characteristic is influenced by parameters such as the pore structure formed during the drying process, freezing rate, rehydration temperature, drying temperature, and drying duration. This study, conducted to determine the effects of freeze-drying (lyophilization) on food, subjected ginger and kiwi samples to a controlled lyophilization process for 14 hours. Product quality and sensory analysis were evaluated after drying for samples with a slice thickness of 7 mm. To analyze the rehydration capacity of the dried samples, rehydration analyses were performed in pure water at temperatures of 30°C, 40°C, and 50°C. The rehydration process in freeze-dried foods and the factors affecting this process were investigated. The experiments revealed that slice thickness affected the drying time, and that increasing the rehydration temperature shortened the rehydration time.
The effects of product structure, drying conditions, and rehydration parameters on rehydration capacity were compared by evaluating studies conducted on different food groups. The aim of this study is to evaluate the data obtained regarding the rehydration properties of freeze-dried foods and contribute to future research.
Keywords: Drying; Freeze-Drying; Rehydration Capacity; Quality Parameters