Interactions between milk whey protein and polysaccharide in solution

Interaction and formation mechanism of binary complex between zein and propylene glycol alginate

The anti-solvent co-precipitation method was used to fabricate the zein-propylene glycol alginate (PGA) binary complex with different mass ratios of zein to PGA (20:1, 10:1, 5:1, 2:1 and 1:1) at pH 4.0. Results showed that attractive electrostatic interaction between zein and PGA occurred and negatively charged binary complex with large size and high turbidity was formed due to the charge neutralization. Hydrogen bonding and hydrophobic effects were involved in the interactions between zein and PGA, leading to the changed secondary structure and improved thermal stability of zein. Aggregates in the irregular shape with large size were obviously observed in the AFM images. PGA alone exhibited a fine filamentous network structure, while zein-PGA binary complex showed a rough branch-like pattern and the surface of "branch" was closely adsorbed by lots of spherical zein particles. Q in zein-PGA binary complex dispersions presented the improved photochemical and thermal stability. The potential mechanism of a two-step process was proposed to explain the formation of zein-PGA binary complexes.

Raman spectroscopic study of structural changes upon chilling storage of frankfurters containing olive oil bulking agents as fat replacers

Technological properties and structural characteristics of proteins and lipids, using Raman spectroscopy, of frankfurters formulated with olive oil bulking agents as animal fat replacers were examined during chilling storage. Frankfurters reformulated with oil bulking agents showed lower (P<0.05) processing loss and higher (P<0.05) hardness and chewiness. Purge loss during chilling storage was relatively low, demonstrating a good water retention in the products. β-Sheet structures were enhanced by the use of olive oil bulking agents, and this effect was more pronounced in samples containing inulin. Reformulated frankfurters contained the least turns (P<0.05). A significant decrease of β-sheets and an increase of turns were observed after 85 days of chilled storage. The lowest (P<0.05) values of IνsCH2/IνasCH2 were recorded in frankfurters reformulated with oil bulking agents, which suggests more lipid acyl chain disorder. Structural characteristics were correlated to processing losses, hardness, and chewiness.

Mixed biopolymer systems based on starch

A binary mixture of starch–starch or starch with other biopolymers such as protein and non-starch polysaccharides could provide a new approach in producing starch-based food products. In the context of food processing, a specific adjustment in the rheological properties plays an important role in regulating production processing and optimizing the applicability, stability, and sensory of the final food products. This review examines various biopolymer mixtures based on starch and the influence of their interaction on physicochemical and rheological properties of the starch-based foods. It is evident that the physicochemical and rheological characteristics of the biopolymers mixture are highly dependent on the type of starch and other biopolymers that make them up mixing ratios, mixing procedure and presence of other food ingredients in the mixture. Understanding these properties will lead to improve the formulation of starch–based foods and minimize the need to resort to chemically modified starch.