Covalent modification of food proteins by plant-based ingredients (polyphenols and organosulphur compounds) : A commonplace reaction with novel utilization potential

Background: Many food ingredients such as polyphenols, phenolic acids (e.g. present in fruit and vegetables) and organosulphur compounds (e.g. present in mustard, garlic and chives) covalently interact with meat, egg, dairy and plant-based proteins. The results of those interactions are manifold and range from altered technological properties (in emulsions, foams, gels) to sensory changes (colour formation, altered taste and smell) and different biological activity (allergy, antimicrobial effects, hydrolysis). Scope and approach: The present review discusses both the positive and the negative side effects of such interactions and explores the potential to fine-tune protein functionality during processing not only in model solutions but also in more complex foods. Key findings and conclusions: Traditionally, studies have focused on the negative effects of interactions between protein and plant ingredients (e.g. discolouration and solubility changes), but more recent studies highlight positive effects (e.g. enhanced emulsifying capacity, reduced allergy and targeted production of protein pigments). By controlling food processing conditions (e.g. protein nativity) and the food matrix (e.g. presence of antioxidative compounds or thiol groups, pH value during storage), the observed effects can be prevented or induced. On the basis of the listed findings, future processes can be developed that take such interactions into account to enable targeted co-processing of plant compounds with proteins. A better understanding of these interactions opens up a wealth of novel utilization potential.</p

Cultivation of shear stress sensitive and tolerant microalgalspecies in a tubular photobioreactor equipped with a centrifugal pump

Paid Open Acces

NEW INSIGHTS IN DOUGH PROCESSING

Mixing is a critical operation in dough processing. Because mixing itself is a complex combination of rotational, shear and elongational deformations, it has always been extremely difficult to understand dough mixing on a mechanistic level. Apart from that, a quantitative relationship between the type of deformation in the mixing and the resulting dough properties is still lacking. This paper reviews our main findings in this field. We focused on the effects of well-defined flow regimes on dough properties to gain a mechanistic insight in dough processing and concluded that simple shear flow and elongational flow influenced material quite differently. In elongational flow, the material was stretched and largely deformed favouring the break-up phenomenon. Simple shear flow caused rotation of protein patches, which promotes colloidal aggregation and local phase separation. High shear rates induced break-up of gluten domains and development of a network without having a severe effect on a molecular scale. The results outlined that it is not the mechanical energy input, but the type of deformation applied that is of crucial importance in dough processing. Dough was rather process tolerant upon simple shearing suggesting clear opportunities for making dough processing milder. Theses findings shed a new light on the concept of under, optimally and over-mixing, and open up interesting possibilities for innovative mixer designs

Challenges and solutions of extracting value-added ingredients from fruit and vegetable by-products : a review

Every year, huge amounts of fruit and vegetable by-products in the food processing factories are produced. These by-products have great potential to be used for different targets especially the extraction of value-added ingredients. The target of this study is to review the challenges of extraction of value-added ingredients from fruit and vegetable by-products on the industrial scale and to describe current trends in solving these problems. In addition, some strategies such as multi-component extraction as well as application of fermentation before or after the extraction process, and production of biofuel, organic fertilizers, animal feeds, etc. on final residues after extraction of value-added ingredients are discussed in this review paper. In fact, simultaneous extraction of different value-added ingredients from fruit and vegetable by-products can increase the extraction efficiency and reduce the cost of value-added ingredients as well as the final volume of these by-products. After extraction of value-added ingredients, the residues can be used to produce biofuels, or they can be used to produce organic fertilizers, animal feeds, etc. Therefore, the application of several appropriate strategies to treat the fruit and vegetable by-products can increase their application, protect the environment, and improve the food economy

A novel process to produce stratified structures in food

A method to create stratified structures with static mixing elements initially developed for the plastic polymer industry is investigated here as a new route for structuring food dispersions. Food dispersions of different viscosities were structured with static mixing elements to investigate the potential of the method for foods. Differently coloured chocolates were used as the model products. The viscosity of the chocolate was controlled through the addition of pea fibre. The first step was the formation of 2–8 layers, with the two differently coloured chocolates. Then, the chocolate dispersions were layered into 256 layers with an approximate layer thickness of 60 μm. Layer formation was facilitated when using similar paste viscosity and when slip was induced through wall coating with vegetable oil. Uniaxial cutting tests of the layered chocolate indicated that layering resulted in different mechanical properties, parallel and perpendicular to the layers. Fibre orientation in the direction of flow was observed, resulting in the potential to induce anisotropy, additional to the layers. The higher viscous dispersions, wheat dough and melt cheese, could also be structured into layers, although the force constraints of the experimental set-up were reached. Mid-stream additions were added to produce strand structures instead of layers, resulting in higher hierarchy structures but less uniformity

Abrasive milling : A method to pre-fractionate testa and embryonic axis from yellow pea

Making use of crops structural break-up during pearling and subsequent fractionation into starch or protein enriched fractions was investigated using stepwise pearling as a method. In first instance, pearling resulted in separation of pea testa and embryonic axis from the cotyledon. Further around 20% of the yellow pea cotyledon was pearled off and collected separately from the inner kernel. All four fractions were finely ground and their composition analysed. Due to the di-cotyledon structure of the pea, solely pearling the outer kernel couldn't be guaranteed. Therefore, the process was repeated by hand-dissection, to ensure only separation of the outer 20% cotyledon. Pearling resulted in size reduction and separation of testa, embryonic axis and the outer and inner part of the cotyledon. Although, no considerable enrichment was achieved in protein or starch content in the pearled fraction of the outer and inner cotyledon, pearling gave the opportunity to obtain the testa fraction, which according to literature is rich in dietary fibre. Moreover, the protein-rich embryonic axis was separated and collected. The testa fraction accounts for 7–8% of the whole pea and contains little protein and starch, which makes it a promising dietary fibre rich ingredient in food application