Structuring meat analogs by citrus fiber with reduced salt intake

In this study, we investigated the effect of addition of citrus fiber (CF; 5% and 10%, which consists mainly of soluble pectin and insoluble cellulose) on physical properties and microstructure of meat analogs based on soy protein isolate and wheat gluten using high-moisture extrusion. Layered structure or microstructure of meat analogs was observed by scanning electron microscope and confocal laser scanning microscope. Compared to the control (without CF), meat analogs with CF addition showed disorder layered microstructure, which was interconnected with smaller fibers. Rheological measurements (strain sweep and frequency sweep) show that the incorporation of CF resulted in meat analogs with softer texture. The moisture content of meat analogs increased significantly upon the addition of CF, which was also correlated with juiciness. Sensory evaluation and dynamic salt release results confirm that the saltiness of meat analogs with CF addition was enhanced due to the structural changes of phase-separated structures, achieving salt reduction by 20% and showing a saltiness similar to the control sample. This research provides a novel approach to modulate the saltiness perception of meat analogs by modifying the phase separation of protein/polysaccharides. PRACTICAL APPLICATION: Citrus fiber is added to the plant protein matrix to prepare meat analogs with high moisture content and enhanced saltiness perception via modifying the phase separation of protein/polysaccharides. This work provided a potential target for the meat industry to produce the meat analogs with less salt intake. Further research can be conducted using modified fibrous or inner structure of meat analogs to improve its quality.

Can Citrus Fiber Improve the Quality of Gluten-Free Breads?

Citrus fiber has a high water absorption capacity, and its properties can be modified by shearing. In this study, the influence of the addition of normal or shear-activated citrus fiber was analyzed in two gluten-free bread formulations. Citrus fiber increases bread optimal hydration and breadcrumb alveolus size due to this high water retention capacity. However, results are negative in the formula based on starches and rice flour because specific volume is significantly reduced, while bread quality improves in the formula based on starches (corn and tapioca). In this case, the breads become less hard and more cohesive, elastic, and resilient, reducing staling. Baking yield also increased due to a greater hydration and a reduced weight loss during baking, without losing acceptability. The mechanical pre-activation of the fiber further increases optimal hydration, without major changes in the quality of the final bread. These effects are associated with cell rupture, and thus the formation of a three-dimensional network, including the increase of surface area and its interaction with water. Citrus fiber increases the hydration of the dough, as well as the cohesiveness, resilience, and elasticity of the crumb, reducing the increase in hardness during storage without affecting acceptability or increasing it.

Effects of Citrus Fiber on the Gel Properties of Mutton Myofibrillar Protein

This work investigated the effects of different additions of water-soluble citrus fiber (SCF) and water-insoluble citrus fiber (ICF) on the gel properties of the mutton myofibrillar protein (MP). The key parameters of water-holding capacity (WHC), rheological properties, and microstructure were evaluated. The addition of 2.5-10% of SCF and ICF significantly improved (p < 0.05) the WHC and gel strength of mutton MP gel. The rheological results showed that the viscoelasticity of MP with 5% SCF was the best, and the T₂ relaxation time of the gel was significantly shortened. SEM results showed SCF reduced the number of pores in the MP gel, forming a more compact network structure. ICF stabilized the MP gel network structure as a filler after water absorption and expansion. However, the gel lost moisture under the action of strong external force (freeze-drying), which left large pores. These data confirmed that SCF and ICF could effectively improve the gel properties of meat products.

Application of Citrus and Apple Fibers for Formulation of Quercetin/Fiber Aggregates: Impact of Quercetin Concentration

Among flavonoids, quercetin has gained special attention due to its positive biological activities. Quercetin's disadvantages, such as its hydrophobic nature, poor solubility, and permeability, could be overcome by complexation with different polymers. Dietary fibers are known as carriers of polyphenols, which can protect them from environmental conditions and thus allow them to be absorbed. In this study, apple and citrus fibers (as applicable food by-products) were used as carriers of quercetin. A constant amount of fibers (1%) and different concentrations of quercetin solution (5 mM, 10 mM, and 20 mM) were complexed. Obtained fiber aggregates were subjected to HPLC to determine the quercetin concentration and antioxidant activity of aggregates (ABTS, DPPH, FRAP, and CUPRAC assays). IR spectra were recorded to confirm complexation of quercetin with selected fibers, and an additional DSC study was performed to evaluate the thermal stability of fiber aggregates. The results of HPLC analysis showed that quercetin had higher affinity towards apple fiber than citrus fiber, without proportional trends of adsorption. Consequently, apple fiber aggregates had higher antioxidant potential than citrus fiber aggregates. FTIR-ATR analysis showed the formation of new bands and the loss of existing bands when quercetin was present. Adsorption of quercetin also had an impact on the thermal stability of formulated fiber aggregates. For apple fiber, this impact was negative, while for citrus fiber, the impact was positive. These results could contribute to greater understanding of quercetin's behavior during the preparation of food additives based on polyphenols and fibers.

Volatiles and Antioxidant Activity of Citrus Fiber/Blackberry Gels: Influence of Sucrose and Trehalose

Citrus fiber/blackberry gels (CBg) can be used for the preparation of various bakery products as well as confectioneries. The objective of this study was to evaluate the influence of the type of disaccharides (sucrose or trehalose) and their percentages (10% or 20%) on volatile compounds as well as phenolics, antioxidant activity and color of formulated CBg. Additionally, CBg were stored at room temperature for 3 months to evaluate their stability. Both disaccharides type and their percentage affected the investigated parameters. Sucrose had a higher positive impact on volatiles after formulation and storage of CBg, while trehalose had a higher positive impact on total phenolics. Amounts of phenolics increased with the increase of disaccharides amount, while the behavior of volatiles also depended on volatiles' properties. Results of this study emphasized the importance of the adequate choice of ingredients for the formulation of high-quality fruit products.

Disaccharide Type Affected Phenolic and Volatile Compounds of Citrus Fiber-Blackberry Cream Fillings

The food industry is continuously developing ingredients, processing methods and packaging materials to improve the quality of fruit products. The aim of this work was to study the possibility of using citrus fiber in the preparation of blackberry cream fillings in combination with disaccharides (sucrose, maltose and trehalose). Evaluations of the phenolics, proanthocyanidins, antioxidant activity, color and volatiles of blackberry cream fillings were conducted after preparation and after three months of storage. Blackberry cream fillings were prepared from citrus fiber (5%), blackberry juice and disaccharides (50%). Disaccharide type had an effect on all investigated parameters. The highest phenol content was in fillings with trehalose (4.977 g/100 g) and the lowest was in fillings prepared with sucrose (4.249 g/100 g). The same tendency was observed after storage. Fillings with maltose had the highest proanthocyanidins content (473.05 mg/100 g) while fillings with sucrose had the lowest amount (299.03 mg/100 g) of these compounds. Regarding volatile compounds, terpenes and aldehydes and ketones were evaluated in the highest concentration. Terpenes were determined in the highest concentration in fillings with trehalose (358.05 µg/kg), while aldehydes and ketones were highest in fillings with sucrose (250.87 µg/kg). After storage, concentration of volatiles decreased. These results indicate that the selection of adequate disaccharides is very important since it can influence the final quality of the product.