A Review on the Relationships between Processing, Food Structure, and Rheological Properties of Plant-Tissue-Based Food Suspensions Katlijn R.N. Moelants, Ruth Cardinaels, Sandy Van Buggenhout, Ann M. Van Loey, Paula Moldenaers, and Marc E. Hendrickx Abstract: Nowadays, there is much interest in controlling the functional properties of processed fruit- and vegetable- derived products, which has stimulated renewed research interest in process–structure–function relations. In this review, we focus on rheology as a functional property because of its importance during the entire production chain up to the moment of consumption and digestion. This review covers the literature of the past decade with respect to process– structure–rheology relations in plant-tissue-based food suspensions. It became clear that the structure of plant-tissue-based food suspensions, consisting of plant-tissue-based particles in an aqueous serum phase, is affected by many unit operations (for example, heat treatment) and that also the sequence of unit operations can have an effect on the final structural properties. Furthermore, particle concentration, particle size, and particle morphology were found to be key structural elements determining the rheological properties of these suspensions comprising low amounts of starch and serum pectin. Since the structure of plant-tissue-based products was shown to be changed during processing, rheological parameters of these products were simultaneously altered. Therefore, this review also comprises a discussion of the effect on rheological properties of the most relevant processing steps in the production of plant-tissue-based products. Linking changes in rheology due to processing with process-induced alterations in structural characteristics turned out to be quite intricate. The current knowledge on process–structure–function relations can form the basis for future improved and novel food process and product design. Introduction Nowadays, a substantial part of the cultivated fruits and vegeta- bles are processed into fluid-like plant-tissue-based food suspen- sions like soups, sauces, and pur´ ees. Plant-tissue-based food sus- pensions, consisting of a particle fraction and a continuous serum phase, are the final result of structure-enabling (including blend- ing, mixing, sieving, high-pressure homogenization [HPH]) and preservation unit operations (such as heating, high-pressure treat- ments) used during production. The structural organization of these suspensions, governing their functional properties, is largely determined by the production process. This provides the oppor- tunity to tailor the functional properties of plant-tissue-based food MS 20131305 Submitted 9/13/2013, Accepted 1/3/2014. Authors Moelants, Van Buggenhout, Van Loey, and Hendrickx are with Laboratory of Food Technology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Dept. of Microbial and Molecular Systems (M2S), KU Leuven, Kasteelpark Arenberg 22, PB 2457, 3001 Leuven, Belgium. Authors Cardinaels and Moldenaers are with Soft Matter, Rheology and Technology, Dept. of Chemical Engineering, KU Leuven, Willem de Croylaan 46, PB 2423, 3001 Leuven, Belgium. Direct inquiries to author Hendrickx (E-mail: Marc.Hendrickx@biw.kuleuven.be). suspensions by means of structure management by the use of tar- geted processing. Therefore, the understanding and quantification of process–structure–function relations has become a key research area and forms the basis for future improved and novel food pro- cess and product design. In this review, the relations between the structural characteristics and the rheological properties of plant- tissue-based food suspensions are summarized based on the re- search results published until now. Moreover, the way processing can be used to rationally direct the structure and, consequently, the rheology of these products is discussed. Despite the impor- tance of this topic for food industry and the timeliness of the topic, a profound review on process–structure–rheology relations in plant-tissue-based food suspensions does not exist at present. This review goes further than most available pectin reviews fo- cusing on process-induced pectin changes with the goal to en- gineer texture of plant-tissue. In this review, it is attempted to link process-induced pectin changes with changes in structural properties of plant-tissue-based particles prepared by the destruc- tion of plant-tissue. Furthermore, the effects of various processing steps used during the preparation of plant-tissue-based food sus- pensions on the rheology of these suspensions are summarized. Finally, the process-induced changes in rheological properties are, C  2014 Institute of Food Technologists ® doi: 10.1111/1541-4337.12059 Vol. 13, 2014  Comprehensive Reviews in Food Science and Food Safety 241