Huizhi Chen

Recent Developments in High-quality Drying of Vegetables, Fruits and Aquatic Products.

ABSTRACT Fresh foods like vegetables, fruits, and aquatic products have high water activity and they are highly heat-sensitive and easily degradable. Dehydration is one of the most common methods used to improve food shelf-life. However, drying methods used for food dehydration must not only be efficient and economic but also yield high-quality products based on flavor, nutrients, color, rehydration, uniformity, appearance, and texture. This paper reviews some new drying technologies developed for dehydration of vegetables, fruits, and aquatic products. These include: infrared drying, microwave drying, radio frequency drying, electrohydrodynamic drying, etc., as well as hybrid drying methods combining two or more different drying techniques. A comprehensive review of recent developments in high-quality drying of vegetables, fruits and aquatic products is presented and recommendations are made for future research.

Comparison of Drying Characteristics and Quality of Shiitake Mushrooms (Lentinus edodes) Using Different Drying Methods

The objective of this study was to compare the drying characteristics and the quality of dried Shiitake mushroom (Lentinus edodes) cubes obtained by hot-air drying (HAD), intermediate-infrared drying (IIRD), and vacuum microwave spouted-bed drying (VMSD). Several quality parameters of products, including color, texture, and rehydration capacity, were investigated. Compared to IIRD and VMSD, HAD turn out to be the most undesirable method due to its longer drying time and poor product quality. With similar rehydration capacity, the color of the VMSD product was closest to the original material. In terms of texture, total sugar content, and sensory evaluation, the VMSD product has the best quality.

Recent Application of Modified Atmosphere Packaging (MAP) in Fresh and Fresh-Cut Foods

Modified atmosphere packaging (MAP) has been applied in the food industry for about 90 years to extend shelf life and maintain quality of fresh and fresh-cut foods. Recently, MAP has experienced a rapid development in both scientific and industrial communities, which was one of the most appropriate and practical technologies for packaging fresh and fresh-cut produce. This paper reviews some recent developments of newly emerged MAP systems such as high-oxygen MAP, controlled MAP, and intelligent MAP and provides an overview of MAP applications for fresh and fresh-cut fruits, vegetables, mushrooms, meat, and aquatic products.

Recent Developments in High-Quality Drying with Energy-Saving Characteristic for Fresh Foods

Combined drying technique can merge the advantages of various drying methods and minimize the limitations of single drying methods, which have the potential to develop an efficient and economical, and high-quality modular dryer for perishable fresh foods. This article reviews evaluation of food high-quality drying and examples of energy-saving techniques in drying technology, then focuses on some novel combined drying technologies with energy-saving characteristics recently developed for dehydration of fresh foods, which include infrared-, microwave-, and radio frequency–related combined drying techniques. Recommendations are also made for future research and development.

Effects of Different Drying Methods on the Quality of Squid Cubes

The effects of three different drying methods (e.g., intermediate infrared-assisted convection drying, low-frequency (915 MHz) microwave drying, and hot-air drying) on the quality of squid cubes were investigated. The quality parameters used to evaluate the drying efficiency were color, shrinkage, rehydration ratio, and hardness of the final dried products. The results showed that intermediate infrared-assisted convection drying and low-frequency microwave drying have the advantages over hot-air drying in terms of drying rate, shrinkage percentage, and rehydration ratio. Low-frequency microwave-dried samples displayed a puffed structure and their hardness was the highest. The intermediate-wave infrared-assisted convection drying, at 60°C, was identified as the best method for squid-cube drying in this study.

Drying and Quality Characteristics of Shredded Squid in an Infrared-Assisted Convective Dryer

Drying is one of the most common methods for processing and preserving squids. A novel forced convective dryer based on infrared heating was developed with an online temperature control. By setting the drying medium temperature of 50°C, we studied the effects of infrared wavelength and air velocity on drying characteristics of the shredded squid and qualities of dried squid products. We also compared it with the conventional hot-air drying (HAD) and advanced microwave vacuum drying (MVD). The infrared heating rate increase was faster than that of HAD. The heating and drying at the wavelength of 2.5–3.0 µm were more effective than those at the infrared wavelength of 5.0–6.0 µm. Specific energy consumption linearly increased with the air velocity. Microstructure observation showed that the infrared-dried rehydrated sample displayed a muscle fiber structure similar to the fresh sample. The infrared-dried squids had less drying shrinkage, brighter color, and better rehydration capacity than HAD products. Their sensory qualities were better than HAD and MVD products. Above all, infrared drying with wavelength of 2.5–3.0 µm and air velocity of 0.5 m/s was suggested as the best drying condition for squids in this study.

Vacuum Frying of Desalted Grass Carp (Ctenopharyngodon idellus) Fillets

The objective of this study was to investigate the effects of vacuum frying on the product quality of desalted grass carp fillets. Parameters of included moisture content, oil content, color values, and textures (hardness, chewiness, and springiness) were used to evaluate the product quality. Results showed that with increasing vacuum frying temperature and time, the moisture content of fillets decreased while the oil content increased, and hardness increased quickly. The hardness and chewiness values of vacuum-fried samples were both higher than those of atmospheric fried samples. However, there was no significant change in L* among four different temperature/vacuum-frying combinations. The results also indicated that vacuum frying at 0.08 MPa and 100°C–110°C for 15 min can produce crisp grass carp fillets with lower moisture and oil contents as well as good color and texture quality.

Ninth Asia-Pacific drying conference (ADC 2017)

The ninth Asia-Pacific drying conference (ADC 2017) was successfully organized under the leadership of Professor Min Zhang of Jiangnan University, Wuxi, P.R. China during September 24–26, 2017. The Conference was inaugurated in the presence of Professor Arun S. Mujumdar, the Founder and Honorary Chairman of the International Drying Symposium (IDS) and Cofounder of the ADC series; Professor Wei Chen, the Vice President of Jiangnan University; and Dr. Xin Xu from China Rural Technology Development Center, Ministry of Science and Technology of the People’s Republic of China. The Conference attracted 207 abstracts from over 250 registered delegates, both from academia and industry, from 22 countries (Fig. 1). Full papers are included in the conference e-proceedings. Selected papers after peer review will be published in a special issue of Drying Technology in 2018. There were one plenary session and 12 oral sessions with a total of 123 oral presentations, including 24 keynote lectures. Additionally, there were 84 posters and an exhibition from 14 industrial companies. Details of the program can be found at the Conference website (http://www. adc2017.org/). The theme for ADC 2017 was “Drying Challenges: Bridging Academia and Industry,” which was achieved through active participation of both parties in the “Industry-University-Research Drying Forum.” Professor Arun S. Mujumdar; Professor Bhesh Bhandari of University of Queensland, Australia, Professor Xiao-Dong Chen of Soochow University; Professor Sakamon Devahastin of King Mongkut’s University of Technology Thonburi, Thailand; and Professor Chung Lim Law of University of Nottingham, Malaysia Campus delivered plenary lectures entitled “Sustainable drying technologies—Role of global R&D,” “Understanding the mechanism and control of crystallization of sugar in dried fruit production,” “Spatially distributed drying system modeling made easy through a reaction engineering approach,” “Commercializing a drying research project: Opportunities, difficulties and challenges,” and “A tale of application of heat pump assisted drying in industry,” respectively. The delegates were inspired by the innovative ideas of the Plenary Speakers about drying technologies and also excited about the successful R&D cooperation achievements of ten leading enterprises that participated. The Conference received generous sponsorships from 12 leading drying-related companies, including Haitong Food Group Co. Ltd., Jiangsu Bolaike Frozen Technology Development Co., Ltd., Changzhou Yibu Drying Equipment Co., Ltd., Guangdong Jiahao Food Co., Ltd., Wuxi Delin Marine Equipment Co., Ltd., Suzhou Niumag Analytical Instrument Corporation, Wuxi Linzhou Drying Equipment Co., Ltd., Xinghua Lianfu Food Co., Ltd., Nanjing Orient Microwave Technology Co., Ltd., Xinjiang Fruit Industry Group Co., Ltd, Mayande Group Co., Ltd., Haoxiangni Jujube Stock Co., Ltd. The success of ADC 2017 was indeed due to the significant tangible contribution of industry in China. Asia-Pacific drying conference 2017 announced five major awards to distinguished scholars in the AsiaPacific region for their outstanding contributions in recent years. These included the A.S. Mujumdar Medal, Bolaike Outstanding Drying Researcher Award, Excellent Drying Research Award, Outstanding Drying Book Award, and Excellent Young Drying Scientist Award. A total of five scholars and two books received these honors. The best oral and poster presentation awards were also announced. Professor Xiao Dong Chen of Soochow University, was presented the ASM Medal, which is recognized internationally as the highest honor for outstanding drying research coupled with outstanding mentorship in drying research. Asia-Pacific drying conference 2017 also incorporated the forth “Food Drying Workshop” into five different sessions. A total of 51 oral presentations were delivered, which focused on the reduction of waste in drying of fruits and vegetables. Excellent feedbacks were received from the participants. At present, energy-saving drying, green drying, and intelligent drying are the main R&D topics for the development none defined