Influence of calcium-binding salts on heat stability and fouling of whey protein isolate dispersions

peer-reviewedThe effect of the calcium-binding salts (CBS), trisodium citrate (TSC), tripotassium citrate (TPC) and disodium hydrogen phosphate (DSHP) at concentrations of 1–45 mm on the heat stability and fouling of whey protein isolate (WPI) dispersions (3%, w/v, protein) was investigated. The WPI dispersions were assessed for heat stability in an oil bath at 95 °C for 30 min, viscosity changes during simulated high-temperature short-time (HTST) and fouling behaviour using a lab-scale fouling rig. Adding CBS at levels of 5–30 mm for TSC and TPC and 25–35 mm for DSHP improved thermal stability of WPI dispersions by decreasing the ionic calcium (Ca2+) concentration; however, lower or higher concentrations destabilised the systems on heating. Adding CBS improved heat transfer during thermal processing, and resulted in lower viscosity and fouling. This study demonstrates that adding CBS is an effective means of increasing WPI protein stability during HTST thermal processing

4-hexylresorcinol and sodium metabisulphite-based edible coatings for avocado shelf-life extension

The short shelf-life of avocados poses problems in the food supply chain, including economic losses due to food waste. This study aimed at developing a new active packaging with antioxidant potential to extend the shelf life of Hass avocados. The fruits were immersed in the solutions of 4-hexylresorcinol (4-HR, 250 and 500 mg/L) and sodium metabisulphite (SMBS, 1250 and 2500 mg/L), labelled as additive-only samples. Another set of samples was prepared by coating the fruits with sodium alginate films (10 g/L) containing the additives (alginate-coated samples). The samples were stored for 10 days at 25 ± 1 °C and 60% RH. Weight loss, total soluble solids (TSS) content, pH, firmness and bioyield point (BYP), internal and external colour and appearance, and microbial load of the samples were investigated on days 1, 5 and 10. Alginate-coated samples had lower weight loss and less increase in the total soluble solids (TSS) and pH values during storage. Firmness values remained similar for all samples from day 1 to 10, regardless of the coating used. Additive-only samples retained the bioyield point (BYP) values, whilst there was a decrease in the alginate-coated samples over 10 days. No differences were observed in the colour parameters (L*, a* and b*) between the additive-only and alginate-coated samples; the latter had a better internal and external appearance. Colour stability was slightly higher when 4-HR was added to alginate coatings than 4-HR as a standalone additive treatment. The microbial enumeration and visual appearance showed that the presence of alginate in the coating had an antimicrobial impact (no surface microbial growth). Alginate-based coatings can be a promising sustainable alternative for maintaining avocado quality during storage

Avocado shelf-life extension using edible active coatings containing 4-hexylresorcinol and sodium metabisulphite

Food waste is a serious environmental and economic challenge worldwide. A total of 2.2 billion tonnes of municipal solid waste per year is expected by 2025. Food packaging is vital in protecting food products from damage and deterioration and helps retain the quality and extend shelf-life. Non-biodegradable packaging has been shown to have serious environmental drawbacks. The current study aimed at developing a new active packaging with antioxidant potential to extend the shelf life of Hass avocados, a short shelf-life fresh produce that poses problems in the food supply chain, including economic losses due to food waste. 4-hexylresorcinol (4-HR, 250 and 500 mg/L) and sodium metabisulphite (SMBS, 1250 and 2500 mg/L), dissolved in water (labelled as additive-only samples) or in sodium alginate film solution (10 g/L) (alginate-coated samples) were used as a coating for ready-to-eat avocados procured from a local supplier in Lincolnshire, UK. The avocados were stored for 10 days at 25 ± 1°C and 60% RH and sampled after 1, 5 and 10 days of storage for weight loss determination, total soluble solids (TSS) content, pH, firmness and bioyield point (BYP), internal and external colour and appearance, lipid oxidation, chlorophyll content and microbial load. Samples coated with alginate lost less weight and soluble solids. While firmness remained similar for all samples from day 1 to 10, regardless of the coating used, the bioyield point (BYP) was retained in additive-only samples. Samples coated with alginate antioxidant packaging had a better internal and external appearance and colour stability than additive-only samples. The results showed that the samples treated with alginate coatings were less prone to oxidation when compared to untreated control samples. In addition, alginate antioxidant coatings had some effect on delayed chlorophyll degradation and a slight reduction in mould and yeast counts. Alginate-based antioxidant coatings can be a promising sustainable alternative for maintaining avocado quality during storage

Ultra high-pressure homogenized emulsions stabilized by sodium caseinate: effects of protein concentration and pressure on emulsions structure and stability

Microstructure, physical properties and oxidative stability of emulsions treated by colloid mill (CM), conventional homogenization (CH, 15 MPa) and ultra-high-pressure homogenization (UHPH, 100–300 MPa) by using different concentrations of 1, 3 and 5 g/100 g of sodium caseinate (SC), were evaluated. The application of UHPH treatment at 200 and 300 MPa resulted in emulsions that were highly stable to creaming and oxidation, especially when the protein content increased from 1 to 3 and 5 g/100 g. Further, increasing the protein content to 3 and 5 g/100 g in UHPH emulsions tended to change the rheological behavior from Newtonian to shear thinning. CH emulsions containing 1 g/100 g of protein exhibited Newtonian flow behavior with lower tendencies to creaming compared to those formulated with 3 or 5 g/100 g. This study has proved that UHPH processing at pressures (200–300 MPa) and in the presence of sufficient amount of sodium caseinate (5 g/100 g), produces emulsions with oil droplets in nano-/submicron scale with a narrow size distribution and high physical and oxidative stabilities, compared to CM and CH treatments

Recent advances in whey processing and valorisation: Technological and environmental perspectives

Whey has several environmental risks if disposed of as waste in watercourses. However, there are numerous valorisation techniques to convert it into a valuable, but also highly products. Techniques such as membrane filtration may be utilised, but these are not applicable to all categories of whey. Novel methodologies that are agile enough to deal with whey variability can produce valorised products. This review assesses the capability of whey processing techniques, applications and methodologies, discussing pertinent research that can innovate product development further. It focuses on environmental impacts of whey as a waste and ways of minimising it

Two-stage valve homogenisation enhances particle dispersion in milk protein concentrates during reconstitution and reduces heat-induced particle aggregation in resultant dispersions

Milk protein concentrates (MPCs) are highly functional ingredients, with high-protein variants increasingly used in numerous applications. The objective of this study was to determine the impact of homogenisation, as part of the rehydration process, on solubility and heat stability of MPC. An 80% protein MPC powder was reconstituted (3% protein, w/v) and homogenised at 50°C using a pilot-scale, two-stage, valve homogeniser at different total pressures of 0, 5, 10, 15 and 20 MPa. Rehydrated samples were analysed for solubility, particle size, protein profile and heat stability (change in particle size distribution on heating in an oil bath at 140°C for 5 min). The results showed a considerable increase in solubility after applying homogenisation at 5 MPa. Homogenisation at pressures of 5-10 MPa reduced particle size of MPC dispersions further, with further increases in pressure having no additional effect. Increased heat stability was observed on increasing homogenisation pressures up to 10 MPa. This work supports previous studies that have demonstratesd the positive impact of homogenisation on particle dispersion in MPCs, but also and identifies a possible link between improved dispersion and heat stability. This would be applied as a strategy in dairy plants to reduce fouling in heat surfaces which suggests a significant economic impact in dairy processing

Impact of oil phase concentration on physical and oxidative stability of oil-in-water emulsions stabilized by sodium caseinate and ultra-high pressure homogenization

In the present study, oil-in-water emulsions were formulated using 5.0% (w/v) of sodium caseinate (SC) and different oil concentrations (10–30%, v/v) by conventional homogenization (CH) and ultra-high pressure homogenization (UHPH, 200–300 MPa). The effect of oil concentration and pressure of treatment on emulsions characteristics and stability was studied. Emulsions were characterized assessing their microstructure, droplet size distribution, rheological properties, emulsifying activity index (EAI), creaming stability by Turbiscan®, and photo-oxidation. UHPH emulsions, especially those treated at 200 MPa, showed smaller droplet size and greater physical stability than CH emulsions. In addition, emulsions containing higher oil volume fractions (20 and 30%) exhibited greater physical and oxidative stability. UHPH emulsions treated at 200 MPa and containing 20% oil content were the most stable emulsions against physical separation and photo-oxidation. These results show that UHPH is a potential technology to enhance the physical and oxidative stability of emulsions containing sodium caseinate as emulsifier for several applications

Microbiological aspects and challenges of whey powders – I thermoduric, thermophilic and spore-forming bacteria

For dairy processors, spoilage and pathogenic spore-forming bacteria are key sources of concern, not only due to their ability to remain dormant in a desiccated state in powders and to survive heat treatments, but also their ability to form biofilms in the vegetative state that lead to contamination of foods. These include members of the genera Bacillus, Geobacillus, Anoxybacillus, Brevibacillus, Paenibacillus and Clostridium, many of which are associated with food poisoning and spoilage. Here, we review the common bacterial species that form spores in whey powders and their sources and provide insights into their risks and strategies to control them

Saltiness perception in gel-based food systems (gels and emulsion-filled gels)

Reducing salt in food without compromising its quality is a huge challenge. Some review articles have been recently published on saltiness perception in some colloidal systems such as emulsions. However, no published reviews are available on saltiness perceptions of gel-based matrices, even though salt release and perception in these systems have been extensively studied. This article reviews the recent advances in salt perception in gel-based systems and provides a detailed analysis of the main factors affecting salt release. Strategies to enhance saltiness perception in gels and emulsion-filled gels are also reviewed. Saltiness perception can be improved through addition of biopolymers (proteins and polysaccharides) due to their ability to modulate texture and/or to adhere to or penetrate through the mucosal membrane on the tongue to prolong sodium retention. The composition of the product and the distribution of salt within the matrix are the two main factors affecting the perception of salty taste. Food structure re-design can lead to control the level of interaction between the salt and other components and change the structure, which in turn affects the mobility and release of the salt. The change of ingredients/matrix can affect the texture of the product, highlighting the importance of sensory evaluation

Turn-key research in food processing and manufacturing for reducing the impact of climate change

This study addresses the critical need to report original and current findings on the global food system's ability to meet the growing natural resource demands of an estimated 9 billion global population. The objective is to provide guidance for researchers in developing strategies to reduce climate change risks in the food and beverage supply. To achieve this, we propose integrating innovative industry insights and digital applications into existing food system models as industrial demonstrators. Our research encompasses six impactful themes, demonstrating effective delivery methodologies. We highlight that human-centred activities and practices, often overlooked in sustainability assessments, hinder improved security and sustainability in the food system. Through our work, we showcase how smarter food production processes, along with active citizen engagement, can achieve desired outcomes outlined in frameworks, such as the Sustainable Development Goals. A crucial aspect is the development of Internet of Things (IoT) platforms, integrating workforce practices into manufacturing activities, and driving the necessary cultural changes for a sustainable food system. This study illuminates challenges faced by the global food system and provides actionable insights and methodologies to guide researchers and industry stakeholders in creating a more sustainable and secure future for food production and consumption