Comparison of citrus pectin and apple pectin in conjugation with soy protein isolate (SPI) under controlled dry-heating conditions

Glycation of Plant Proteins Via Maillard Reaction: Reaction Chemistry, Technofunctional Properties, and Potential Food Application

Plant proteins are being considered to become the most important protein source of the future, and to do so, they must be able to replace the animal-derived proteins currently in use as techno-functional food ingredients. This poses challenges because plant proteins are oftentimes storage proteins with a high molecular weight and low water solubility. One promising approach to overcome these limitations is the glycation of plant proteins. The covalent bonding between the proteins and different carbohydrates created via the initial stage of the Maillard reaction can improve the techno-functional characteristics of these proteins without the involvement of potentially toxic chemicals. However, compared to studies with animal-derived proteins, glycation studies on plant proteins are currently still underrepresented in literature. This review provides an overview of the existing studies on the glycation of the major groups of plant proteins with different carbohydrates using different preparation methods. Emphasis is put on the reaction conditions used for glycation as well as the modifications to physicochemical properties and techno-functionality. Different applications of these glycated plant proteins in emulsions, foams, films, and encapsulation systems are introduced. Another focus lies on the reaction chemistry of the Maillard reaction and ways to harness it for controlled glycation and to limit the formation of undesired advanced glycation products. Finally, challenges related to the controlled glycation of plant proteins to improve their properties are discussed.

Laccase-catalyzed conjugation of potato protein (PPT) with selected pectic polysaccharides (PPS): Conjugation efficiency and emulsification properties

The current study focused on the investigation of laccase-catalyzed conjugation of potato protein (PPT) with selected pectic polysaccharides (PPS) and modulation of the conjugation in order to obtain desired functional ingredients. PPS, including sugar beet pectin/arabinan, apple/citrus pectin and potato galactan, were evaluated as substrates in the conjugation reaction-catalyzed by laccases (Trametes versicolor-LacTv, Coriolus hirsutus-LacCh). LacCh exhibited a higher catalytic efficiency than LacTv. The reactivity of PPT/PPS and their ratio were determinants for their heteroconjugation. Both laccases exhibited the highest specificity towards the conjugation of PPT/sugar beet pectin. Predictive models were developed for conjugation efficiency and emulsification performance. The conjugation extent was negatively affected by the protein proportion and the protein proportion/enzyme concentration interaction; while the emulsification performance was positively correlated with the protein proportion and the protein proportion/reaction time interaction. This study contributed to the understanding of laccase-catalyzed conjugation reaction for the controlled synthesis of conjugated-PTT as functional ingredients.

Improving the functional properties of bovine serum albumin-glucose conjugates in natural deep eutectic solvents

Glycation between target proteins and saccharides is time-consuming or requires high temperatures. Here, a promising reaction medium, natural deep eutectic solvents (NADES), for glucose glycation with bovine serum albumin (BSA) was applied to improve the grafting of glucose-glycated BSA by shifting reaction equilibrium. Two types of glucose-glycated BSA products were prepared using NADES and water systems. SDS-PAGE and MALDI-TOF-MS revealed that BSA and glucose were covalently bonded. Compared with in water system, glycated BSA products in NADES system had more -OH groups, more disordered secondary structures, lower intrinsic fluorescence intensity, and higher ultraviolet-visible absorption. Lower surface hydrophobicity (1100 versus 1356), higher emulsifying activity index (66.17 versus 46.49 m²/g), higher emulsion stability index (79.62 versus 63.61%), and lesser free sulfhydryl (8.07 versus 8.98 μmol/g) groups were obtained with NADES system than with water system. The results suggest that NADES is a suitable alternative reaction medium for promoting the glycation of BSA.

A Review on the Feedstocks for the Sustainable Production of Bioactive Compounds in Biorefineries

Since 2015, the sustainable development goals of the United Nations established a route map to achieve a sustainable society, pushing the industry to aim for sustainable processes. Biorefineries have been studied as the technological scheme to process integrally renewable resources. The so-called “bioactive” compounds (BACs) have been of high interest, given their high added value and potential application in pharmaceutics and health, among others. However, there are still elements to be addressed to consider them as economic drivers of sustainable processes. First, BACs can be produced from many sources and it is important to identify feedstocks for this purpose. Second, a sustainable production process should also consider valorizing the remaining components. Finally, feedstock availability plays an important role in affecting the process scale, logistics, and feasibility. This work consists of a review on the feedstocks for the sustainable production of BACs in biorefineries, covering the type of BAC, composition, and availability. Some example biorefineries are proposed using wheat straw, hemp and grapevine shoots. As a main conclusion, multiple raw materials have the potential to obtain BACs that can become economic drivers of biorefineries. This is an interesting outlook, as the integral use of the feedstocks may not only allow obtaining different types of BACs, but also other fiber products and energy for the process self-supply.