This work deals with the manufacture of oil-in-water food emulsions stabilised by tuna proteins. The influence of protein and oil concentrations on the linear viscoelastic properties and microstructure of these emulsions was analysed. Stable emulsions with suitable linear viscoelastic response and microstructural characteristics were formulated with 70 wt.% oil and, at least, 0.25 wt.% tuna protein. Similarly, emulsions with oil concentrations between 45 and 70 wt.% were prepared using 0.50 wt.% protein. All these emulsions showed a predominantly elastic response in the linear viscoelastic region and a well-developed plateau region in its mechanical spectrum. Rheological and droplet size distribution results pointed out an extensive droplet flocculation, due to interactions among emulsifier molecules located at the oil–water interface of adjacent droplets. As a result, the linear viscoelastic behaviour was controlled by protein–protein interactions, allowing the use of the plateau modulus to successfully normalise both the storage and loss moduli as a function of frequency onto a master curve, irrespective of the selected emulsion formulation.

The microstructure and stability of oil-in-water emulsions, stabilized with non-protein emulsifiers (sorbitan esters), were analyzed as a function of emulsification time, rotor speed, hydrophilic-lipophilic balance (HLB), and ionic strength. Sauter average dia (D[3,2]) were determined from micrographs. Back-scattered light data were analyzed and a method to determine creaming rates of the systems was proposed. Creaming rates showed that the relationship between emulsion stability and HLB was non-linear. Addition of NaCl raised creaming rates, resulting in decreased stability, while micrographs showed the presence of flocs. Results were discussed taking account of interactions present in the system.

Hydrophobic materials extracted from citrus wastes, both peel of mandarin fruits and leaf of mandarin trees were used to treat food-grade Kraft paper. The chemical compounds of the extracts were identified by gas chromatography–mass spectroscopy and infrared spectroscopy, and their antioxidant activities were determined using a free radical scavenger agent (2,2-diphenyl-1-picryl-hydrazyl-hydrate, DPPH). Water vapor permeability, air transmission rate, peroxide value, and microstructure of treated and original papers were also determined. The experimental results showed that: (i) most components of the peel or peel/leaf extracts were terpenes; (ii) free volume existed among cellulose macromolecule chains of the original paper, occupied by a part of extract materials, and another part of the extracts was formed a thin layer on the paper surfaces; and (iii) air and water barrier properties and antioxidant activity of the treated papers were improved, indicating that the extracts were efficient materials for food packaging applications.

In this work, the effects of refrigerator freezing method (RF), spiral tunnel freezing method (SF), and liquid nitrogen spray freezing method (LF) on water distribution, microstructure, retrogradation, and digestion properties of Liangpi are investigated. Results from SEM and water distribution show the starch gel structure of Liangpi after LF treatment is more continuous, and its A₂₁ content is higher, which are closer to fresh Liangpi, followed by SF and RF. XRD and FT‐IR data indicate that as the freezing rate increases, the relative crystallinity and R₁₀₄₇/₁₀₂₂ value of the samples decrease. This is consistent with the data obtained from texture properties. Texture properties of samples treat by LF and SF are closer to fresh Liangpi, especially the hardness index. The in vitro digestibility of Liangpi also shows the same trend. Therefore, the freezing method with a faster rate could inhibit the starch gel retrogradation, improve the texture properties of Liangpi, and guarantee the quality of Liangpi. However, considering the economics of enterprise production, the spiral tunnel freezing method is more suitable for the actual production of frozen Liangpi. The data obtained provide a theoretical guidance for the actual production of frozen Liangpi.

Food gels prepared from the water extract of fish scales (WEFS) are described in this study. The effects of WEFS, sucrose, and NaCl concentration on gel formation and stability, gel texture, and gel sensory attributes were evaluated. The results indicated that an increase in WEFS concentration led to increases in the formation rate, stability, and texture of the gel. Addition of a moderate amount of sucrose (2%–3%, w/v) and NaCl (0.4%–0.6%, w/v) improved the stability, gumminess, chewiness, and cohesiveness of the gel. However, the addition of an excessive amount of sucrose (>4%, w/v) and NaCl (>0.8%, w/v) decreased the stability, gel strength, adhesiveness, and springiness of the gel. The sensory attributes of fish scales (FS) gels were mainly affected by WEFS concentration. On the basis of combined textural analysis and sensory evaluation, the FS gels formed with 4% WEFS, 3% sucrose, or 0.4% NaCl was proposed in this study. The gel microstructure and water distribution obviously showed an apparent variation, together with a change in the structure of FS gels. Competing hydrophilic forces and electrostatic interactions varied with sucrose and NaCl concentration, altering the structure and water distribution of FS gels.

In this study, oil-in-water emulsions made of medium-chain triglycerides (MCT), mucilage from Dioscorea opposita (DOM), and food-grade polysaccharides (guar gum [GG], xanthan gum [XG] and pectin [Pec]) were prepared using high-pressure homogenisation. The droplet size distributions, microstructure, turbidity, interfacial tension, creaming index, and stability of emulsions were investigated and compared with those of DOM, GG, XG and Pec. The results showed that 0.4 wt% food-grade polysaccharides (GG, XG, and Pec) with 2 wt% DOM contributed more to the stability of the emulsion during storage. In particular, low concentrations of pectin and DOM emulsions presented smaller droplet size distribution, in the range of 86.34–111.30 nm. Hence, DOM has synergistic effects with food-grade polysaccharides, which could improve the stability of emulsions, suggesting that mucilage from Dioscorea opposita has good potential for use as a natural emulsifier.

Food reformulation, either to reduce nutrient content or to enhance satiety, can negatively impact upon sensory characteristics and hedonic appeal, whilst altering satiety expectations. Within numerous food systems, perception of certain sensory attributes, known as satiety-relevant sensory cues, have been shown to play a role in food intake behaviour. Emulsions are a common food structure; their very nature encourages reformulation through structural design approaches. Manipulation of emulsion design has been shown to change perceptions of certain sensory attributes and hedonic appeal, but the role of emulsions in food intake behaviour is less clear. With previous research yet to identify emulsion designs which promote attributes that act as satiety-relevant sensory cues within emulsion based foods, this paper investigates the effect of oil droplet size (d4,3: 0.2–50μm) and flavour type (Vanilla, Cream and No flavour) on sensory perception, hedonics and expected food intake behaviour. By identifying these attributes, this approach will allow the use of emulsion design approaches to promote the sensory characteristics that act as satiety-relevant sensory cues and/or are related to hedonic appeal. Male participants (n=24) assessed the emulsions. Oil droplet size resulted in significant differences (P<0.05) in ratings of Vanilla and Cream flavour intensity, Thickness, Smoothness, Creamy Mouthfeel, Creaminess, Liking, Expected Filling and Expected Hunger in 1h’s time. Flavour type resulted in significant differences (P<0.05) in ratings of Vanilla and Cream flavour intensity, Sweetness and Liking. The most substantial finding was that by decreasing oil droplet size, Creaminess perception significantly increased. This significantly increases hedonic appeal, in addition to increasing ratings of Expected Filling and decreased Expected Hunger in 1h’s time, independently of energy content. If this finding is related to actual eating behaviour, a key target attribute will have been identified which can be manipulated through an emulsions droplet size, allowing the design of hedonically appropriate satiating foods.

The addition of dietary fibers can alleviate the deteriorated textural properties and water binding capacity (WBC) that may occur when the fat content is lowered directly in the formulas of comminuted meat products. This study investigated the effects of the addition of chitosan or carboxymethyl cellulose (CMC) (2% w/w) to a model meat product. Both dietary fibers improved the water-binding capacity (WBC), while chitosan addition resulted in a firmer texture, CMC lowered the hardness. Chitosan addition resulted in a 2-fold reduction of lipid oxidation products, whereas CMC had no significant effect on oxidation. The effect of chitosan addition on lipid oxidation was evident both in the meat system and after simulated in vitro gastrointestinal digestion. Low-field nuclear magnetic resonance (NMR) relaxometry revealed that the fibers impacted the intrinsic water differently; the addition of chitosan resulted in a faster T₂ relaxation time corresponding to water entrapped in a more dense pore network. Coherent anti-Stokes Raman scattering (CARS) microscopy was for the first time applied in a meat product to study the microstructure, which revealed that the two fibers exerted different effects on the size and entrapment of fat droplets in the protein network, which probably explain the mechanisms by which chitosan reduced lipid oxidation in the system.

The present study aimed: (i) to develop models for the combined effect of water activity (0.99, 0.94 and 0.90), microstructure expressed as 0, 5, 10 and 20% w/v gelatin, and temperature (15, 20 and 25 °C), on growth and OTA production rates by Aspergillus carbonarius; and (ii) to evaluate the performance of the developed models on food matrices (jelly, custard and marmalade) of different viscosity at pH 5.5. The square root of biomass increase rate (fungal growth rate) and OTA production rate were determined by the Baranyi model and were further modeled as a function of temperature, gelatin concentration and aw by applying polynomial models. Time for visible growth and the upper asymptote of the OTA production curve were also determined by the Baranyi model. Increase in gelatin concentration resulted in a significant delay in all parameters describing fungal growth and OTA production rates, at all temperatures and aw. The effect of microstructure on fungal growth and OTA production rates was less evident at stress conditions of aw and temperature. Detection time for visible fungal growth was markedly influenced by aw and temperature. Coefficients of determination were 0.899 and 0.887 for the models predicting the square root (μₘₐₓ) of growth and OTA production rate, respectively. Predictions of growth rate agreed well with the recorded data of custard and marmalade, while observations of OTA production rate indicated low agreement with model predictions, in all food matrices except for marmalade. The present findings may provide a basis for reliable assessment of the risk of fungal growth and OTA production in foods of different structural and rheological properties.

High GI carbohydrates are associated with several diseases, including diabetes, obesity, and cardiovascular disease (CVD). The rate of starch digestion and absorption significantly impacts metabolic responses. Slowly digestible carbohydrates are advantageous for managing metabolic disorders such as diabetes and hyperlipidaemia and are found in legumes, pasta, and whole-grain cereals. Peas, a high-quality protein source, are typically consumed after soaking and cooking. Pea cooking water is the by-product of split yellow peas, often regarded as an ideal egg white substitute in bakery products due to its emulsifying properties. Pea cooking water (PCW) was recently reported to be rich in proteins, fibres and micronutrients. However, current research has not specifically investigated the nutritional aspects of pea cooking water, although significant nutrient loss is known to occur during cooking. This study investigated the potential of pea cooking water to manage glycaemic responses in carbohydrate-rich foods by examining its effects on human glycaemic levels as well as the structural and textural properties of these foods. This study examines the structural and nutritional modifications that occour to pasta when PCW or pea flour (PF) are incorporated into the formulation. The inclusion of freeze-dried PCW (PCWFD) in pasta significantly (P<0.05) reduced the optimal cooking time (OCT) and altered water absorption capacity due to its unique structural attributes. Compared to traditional wheat pasta, PCWP exhibited a lower OCT (P<0.05), reduced swelling index (P<0.05), and higher cooking loss when substituting 20% of semolina with PCWFD (P<0.05). Additionally, pasta substituted semlina with 10% and 20% PCWFD showed increased tensile strength and decreased cutting force (P<0.05), maintaining an intact microstructure and consistent particle size distribution. The incorporation of PCWFD modified protein-starch network of the pasta. The modified protein-starch networks in PCWP and PFP resulted in slower glucose release and a lower glycaemic response (P<0.05). The study explored the impact of varying cooking times and PCWFD levels, finding that longer cooking times and higher PCWFD concentrations affect cooking loss and water absorption, influencing glycaemic response. PCWP performs comparably or better than traditional pea flour pasta in in vitro glucose digestion tests. The food matrix does not disrupt the effect of PCW in reducing and slowing glucose release, as demonstrated by comparisons with rice boiled in PCW versus normal water. PCW incorporation significantly reduced postprandial glycaemic responses in human subjects (P<0.05), attributed to the high protein content and fibre effects on gastric emptying. The lower glycaemic index (GI) effect is also due to the higher protein content, lower starch content, and protein-starch interactions. Despite a fully gelatinized structure, PCWP maintain a reduced glycaemic response. These findings highlight the potential of PCW as a functional ingredient to enhance the nutritional profile of pasta, reduce glycaemic responses, and promote sustainable food processing practices. The present work addressed the potential health benefits of PCW to develop of functional food by investigating the effect on human postprandial glycaemic response. It represented a functional and innovative approach to food development while promoting environmentally sustainable practices.