Food rheology applications of large amplitude oscillation shear (LAOS)

Background: Classical flow and small amplitude oscillation shear (SAOS) often do not meet the emerging needs of food research in practical scenarios to provide food texture information for processing in similar mechanical deformation range. Large amplitude oscillation shear (LAOS) has been developing rapidly in the last decade, but is yet to be widely used in food rheology due to the uncertainty of which LAOS analytical tools are most suitable for particular types of foods. Scope and approach: This review aims to provide a significant update on the recent application of LAOS for different types of foods. While a brief summary of common analytical tools used in food LAOS rheology is given, the focus of this paper is on the use of LAOS for different food macro components (proteins, polysaccharides, fats), food formats (emulsion, foam), and categories (dough, cheese, confectionery). The applicable LAOS analytical tools and typical results in each category are presented. Key findings and conclusions: The common tools in food LAOS rheology include strain curve shape analysis (strain/amplitude sweep), Lissajous curve analysis (raw/elastic/viscous/3D Lissajous curves and Pipkin diagram), and nonlinear viscoelastic parameters (higher harmonic intensities, strain-stiffening/thickening ratios, large/minimum strain modulus/viscosities, etc.). Different tools were found to suit the analysis of different food components or categories. LAOS rheological analysis of foods can provide a richer dimension than the traditional SAOS analysis, particularly in understanding the phase change processes of food ingredients and the effects of food processing on food structure

Dairy encapsulation systems by atomisation-based technology

Edited by a team of distinguished researchers affiliated to CSIRO, this book is a valuable resource to all involved with the Food Industry and Academia

Microencapsulation of active ingredients in functional foods: From research stage to commercial food products

Background: Twelves categories of active ingredients have been recognised to enhance human health. They are to some extent susceptible to certain conditions such as heat, light and low pH. To reduce their susceptibility and achieve controlled release at the target site, various microencapsulation strategies have been introduced. Scope and approach: In this review, the chemical structures, physicochemical properties and beneficial effects of the active components are summarised. Different encapsulation techniques and tailored shell materials have been investigated to optimise the functional properties of microcapsules. Several encapsulated constituents (e.g., amino acids) have been successfully incorporated into food products while others such as lactic acid bacteria are mostly used in the free format. Encapsulating some of these active ingredients will extend their ability to withstand process conditions such as heat and shear, and prolong their shelf stability. Key findings and conclusions: The functional properties of a microcapsule are encapsulation efficiency, size, morphology, stability, and release characteristics. Several microencapsulation strategies include the use of double emulsions, hybrid wall materials and crosslinkers, increasing intermolecular attraction between shell and core, physical shielding of shell materials, and the addition of certain ions. Other approaches such as the use of hardening agents, nanoencapsulation, or secondary core materials, and the choice of shell materials possessing specific interactions with the core may be used to achieve targeted release of active ingredients. The physicochemical properties of shell materials influence where the active ingredients will be released in vivo. A suitable microencapsulation strategy of active ingredients will therefore expand their applications in the functional foods industry

Prediction of zeta potential of amaranth protein isolate via artificial neural networks using the electrostatic surface potential of 11S proglobulin

Plant proteins have attracted significant attention due to various health concerns and food safety issues related to animal-based proteins. Different physical and chemical approaches have been applied to plant proteins to improve their functionality, including chemical, physical, or combination of treatments. One of the main properties of interest is the zeta potential as a measure of surface charge. It can be used to optimize the suspension formulations, estimate the emulsion stability, or predict the food surface interactions. Here, we used a single protein database sequence of a plant protein (11S proglobulin) to obtain the net electrostatic surface potentials at different pH. These values were used for modelling a primary neural network to find a correlation between the measured zeta potential and the calculated electrostatic potential values. The network created by this approach had a high correlation coefficient (R = 0.99) for predicting the electrostatic or zeta potential at various pH for the Amarantin. The study demonstrates the potential use of an artificial neural network and its analysis to predict zeta potential values over a pH range, once the network is trained with appropriate datasets, which can potentially be implemented over a range of other plant proteins. The limitation in theoretical protein models, including the complexity of the protein structures and pH-dependent changes of amino acids, must be considered when developing such models. This approach can be explored further to consider protein interactions in the presence of buffer or with added electrolytes, including changes in the surface charge of the molecules

Modification of molecular conformation of spray-dried whey protein microparticles improving digestibility and release characteristics

This study reports on the preparation of riboflavin-loaded whey protein isolate (WPI) microparticles, using desolvation and then spray drying. Ethanol desolvation led to the exposure of embedded hydrophobic amino acids of WPI to riboflavin, facilitating the formation of riboflavin-WPI complexes. The extent of desolvation and cross-linking influenced the morphology of the spray-dried microparticles, while the moisture content of microparticles decreased with desolvation and increased with crosslinking. The modification of WPI conformation upon desolvation could be retained in the dry state via spray drying. The gastric resistance, release site and release characteristics of microparticles were readily adjusted by varying the ethanol and calcium ion contents from 0 to 50% v/v and from 0 to 2 mM, respectively. The sample prepared from 30% v/v ethanol without calcium crosslinking displayed rapid peptic digestion in less than 30 min. The samples from 30% v/v ethanol at 1 and 2 mM Ca 2+ exhibited excellent gastric resistance and intestinal release

Impact of sodium alginate on binary whey/pea protein-stabilised emulsions

This study aims to understand impact of sodium alginate addition on binary whey/pea protein-stabilised emulsions at various pH. The properties and stability of binary whey/pea protein-stabilised emulsions were characterised by microstructural analysis, droplet size, creaming index in comparison to sole proteins. Protein composition at oil/water interface was examined via SDS-PAGE. Alginate incorporation reduced the droplet sizes and enhanced the emulsion stability at pH 6.6. At pH 11.0, protein only-stabilised emulsion was stable for 21 days, while alginate addition resulted in phase separation in the binary whey/pea protein-stabilised emulsions. The presence of alginate promoted protein adsorption at all pH with both proteins present at the interface. Whey protein displaced pea protein in the binary whey/pea protein-stabilised emulsions over time, whereas alginate addition prevented pea protein from being replaced by whey protein during storage, enhancing their stability. Binary whey/pea proteins with sodium alginate are promising emulsifiers with potential application for liquid creamers

Spray-drying to improve the functionality of amaranth protein via ultrasonic-assisted Maillard conjugation with red seaweed polysaccharide

Maillard conjugation has gained attention for its application in improving functional-properties of different plant proteins, including solubility and emulsification. Amaranth, a plant protein showing a higher lysine-content essential for conjugation, was conjugated with Gracilaria secundata polysaccharide via ultrasonic-assisted Maillard-conjugation. Post-ultrasonication, the outcomes from spray-drying as an alternative to freeze-drying were investigated. The comparison was based on conjugation-degree, solubility, water-or-oil holding capacity, and secondary structural changes in proteins. The protein: polysaccharide (w/w) of 1:1 and 2:1 displayed better conjugation, improved functional and structural aspects including the changes in the amide regions, oil-and-water holding capacity of the protein. Lower degree of conjugation, structural and functional changes for 1:2 samples can be the result of higher polysaccharide content leading to a shielding-effect over the reaction terminals of proteins. A significant difference between the properties was observed with different drying methods. Except for similar conjugation efficiency, the freeze-dried samples exhibited better oil-holding capacity, while the spray-dried samples performed better in water-holding capacity. The difference between spray-drying and freeze-drying could be due to the temperature difference resulting in protein denaturation, or the advancement of Maillard reaction. We demonstrated that spray-drying could be utilized as an alternative to freeze-drying step during ultrasonic-assisted Maillard conjugation, although a focus on optimization of conjugation and spray-drying parameters is required

pH effect on the physico-chemical, microstructural and sensorial properties of processed cheese manufactured with various starches

Processed cheeses containing 5% w/w potato, waxy maize or corn starch were manufactured in the pH range 4.5–6 to investigate the effect of pH on the physical and microstructural characteristics of high-starch processed cheese. Increased hydrogen bonding between the starch alcohol groups and hydrophilic protein residues was observed with both increasing and decreasing pH, indicating a higher degree of starch distribution. Optical microscopy showed a continuous starch exclusion network in cheeses manufactured with native starch between pH 4.8–5.3, with discrete starch particles present at increased and decreased pH. This network breakdown reduced product hardness and increased meltability, with the 5% starch cheese manufactured at pH 6 exhibiting higher sensory acceptability compared to the non pH modified sample. The present work demonstrates that increasing cheese pH during manufacture can reduce the negative physical characteristics associated with high-starch processed cheese and may provide industry with a cost effective method to increase the sensory acceptance of such products

A review on technological parameters and recent advances in the fortification of processed cheese

Background: Although the consumption of processed foods is growing in overseas markets, the increased awareness of consumers to health and wellbeing in recent years has led to a decline in the growth of processed food sales in the Western market. The added pressure on the food manufacturing industry to increase the perceived healthiness of processed foods has opened up new market potential in the area of fortified processed foods, such as processed cheeses. Scope and approach: This review paper provides an overview of the current methodologies into the production of a processed cheese with added health benefits, including the use of probiotics and prebiotics, vitamin and mineral fortification and the addition of plant macromolecules. Key findings and conclusions: Processed cheeses with increased health benefits have been of great interest to manufacturers, with reduced salt and reduced fat options commercially available. Although processed cheeses fortified with vitamins, mineral, probiotics and prebiotics are not as widespread, further work in these areas has been identified as a way to produce high value processed cheese products with added health benefits