Citrus Fiber Research Articles

Impact of processing and storage on citrus fiber functionality: Insights from spectroscopic techniques

To deliver their functionality when used in applications, citrus fibers need to be rehydrated. Factors such as chemical composition, structural organization as well as chemical surface composition are known to influence this functionality. Processing and storage conditions can affect these parameters, making it challenging to maintain stable functionality. This study used Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) to evaluate the effects of preparation and storage on citrus fibers. Samples dried at different scales and stored for 360 days under room and accelerated conditions were assessed for water holding capacity (WHC), water swelling capacity (WSC), and gel rigidity (G′). The results showed a decline in WHC, WSC, and G′ over time, confirming that aging negatively impacts moisture retention, particularly under higher water content or temperature. Drying scale had no effect on chemical composition or structure, but changes in the elemental surface composition of carbon and oxygen were noted. While prolonged storage altered the polysaccharides' chemical composition and structure, leading to functionality loss, XPS analysis revealed no changes in surface composition. Loss of functionality cannot be explained by chemical surface composition modifications.

Preparation of citrus fiber from lemon peel residue: Effects of structure and endogenous pectin components on emulsifying properties of citrus fiber

Preparation of citrus fiber from lemon peel residue: Effects of structure and endogenous pectin components on emulsifying properties of citrus fiber

Citrus fibers improve rheology of OSA starch-based high internal phase emulsion for 3D printed elderly foods

3D printing ready-to-eat emulsions using trans-fat-free edible oil, presents a significant challenge due to the complexities involved in achieving the necessary material structure, rheological properties, and stability. This study fabricated High Internal Phase Emulsions (HIPEs) stabilized with citrus fibers and octenyl succinic anhydride (OSA) modified waxy starch, serving as the printable inks for 3D-printable elderly foods. These printable inks exhibited a pseudoplastic gel structure, which provided enhanced extrudability and improved shape retention. The incorporation of citrus fiber, water, OSA starch, sunflower oil at a concentration of 0.3 wt%, 22.7 % wt %, 2 % wt%, 75 wt% in the 3D-printed HIPEs resulted in optimal addition, yielding the highest level of shape accuracy. Compared to the addition of OSA-modified starch, microstructural analysis and rheological testing (using Lissajous-Bowditch plots) indicated that the addition of citrus fiber had a greater impact on the rheological and textural properties of the HIPEs, which improved shape retention and fluidity of the HIPEs, and ensure the stability of continuous extrusion printing. Additionally, bionic tribological properties demonstrated that tribological properties of the prepared HIPEs were very close to the ones of mayonnaise, which indicating that the prepared HIPEs had smooth texture and easy-to-chew properties for the elderly. These findings offered a comprehensive understanding of the structure–function relationship between the molecular structures of HIPEs and their 3D printability, providing technical insights for the development of 3D-printed emulsion-based ready-to-eat elderly food products. This study provided a good industrialized method for HIPEs stabilized with only fruit dietary fiber and modified starch, and facilitated the development of emulsion-based ready-to-eat food products with 3D printability.

New insights into the strengthening of fibre-based emulsion gels by phenolic compounds

Consumer demand for plant-based meat alternatives and health concerns over animal fats have propelled the exploration of edible oil structuring techniques, for mimicking animal fat texture and functionality. In this context, the use of food polymers offers possibilities in conferring viscoelastic properties to oil structured in heterogeneous systems. Many reported examples were predominantly structured by proteins, however, which are sensitive to ionic strength. In this work, we offer an alternative approach through emulsion gel structuring using curdlan and citrus fibre, which are natural and more process-stable food polymers. This work reports insights gained on emulsion gel strengthening with the use of laccase-oxidised phenolic compounds. Our key results reveal the use of laccase-oxidised ferulic acid at millimolar concentration against 10 % (w/w) curdlan to be particularly promising, in that (i) it strengthened inter-triplex network in heat-set curdlan, as supported by the increase in glass transition temperature of curdlan; (ii) it generated quinones as determined by nitro blue tetrazolium-glycinate assay, which could crosslink interfacial fibre having trace nitrogen; and (iii) consequently, the emulsion gel system became stronger against high strain compression. Crosslinking at inter-oil-droplet bridges with well-controlled oil aggregate sizes was pivotal, and this could be optimised with suitable sequencing of formulation steps that keep the aqueous phase viscosity low during emulsification. Overall, our findings provide reference value in the creation of stiff animal fat mimetics out of unsaturated edible oils.

Effect of citrus fiber on physicochemical quality of Frankfurter sausages: A study on lipid oxidation and protein gel characteristics

Citrus fibers (CF) are frequently used to enhance the water-holding capacity and nutritional profile of meat products. However, their impact on the lipid oxidation and gel properties of emulsified meat products remains incompletely elucidated. This study aims to comprehensively assess the physicochemical and sensory attributes of frankfurter sausages enriched with CF and elucidate the underlying mechanisms. The properties of lipid oxidation, protein intermolecular interactions, and microstructural changes in CF-enriched frankfurter sausages were investigated. The results indicate the potential role of flavonoids contained in CF in preventing lipid oxidation in frankfurters sausages. Furthermore, the incorporation of CF contributes to the formation of a denser microstructure, achieved through the exposure of protein hydrophobic groups and the transformation of α-helical structures into β-turn configurations. These findings advance the understanding of how CF impacts the quality of frankfurter sausages, offering insights for improving the utilization of CF resources and developing higher-value functional meat products.

Mayonnaise produced by ultrasound-assisted emulsification using plant-based and “clean label” ingredients

Recently, nanoemulsions have gained significant attention for their improved stability and their wide range of potential uses in the food industry. This study aimed to create a novel type of mayonnaise with 23.6% (w/w) of oil using ultrasound-assisted emulsification for 6 min to incorporate lupin protein (3.4%, w/w) in the nanoemulsion stabilized by a combination of citrus fibre (2.5%, w/w) and psyllium (0.3%, w/w) or modified starch (3.0%, w/w). Nanoemulsions were produced using a cold-water bath and characterised by their stability and structural properties and used for the production of the mayonnaise. Results showed that the use of lupin protein led to stable nanoemulsions for 50 days stored at 4 °C. The smallest mean droplet size for lupin protein was 505.5 ± 43.5 nm and a polydispersity value 0.434 ± 0.045. Then, the selected nanomulsion was used to produce mayonnaise at room temperature. Mayonnaise were characterised in terms of its rheological and morphological properties, and through sensorial evaluation. The texture of the plant-based formulations was very close to one commercial mayonnaise, with similar resistance to deformation. The consistency (k) and flow index (n) were similar between samples and indicate that the samples are viscous due to the considerable value of k. A sensory analysis with a panel of consumers showed that the proposed formulations had a similar organoleptic profile compared to the benchmark sample. However, the tests showed that formulation developed with fibres had a slightly lower overall liking score.Ultrasound seems to be an effective strategy for developing plant-based nanoemulsions, foreseeing their use in the production of mayonnaise.

Food-grade emulsion gels and oleogels prepared by all-natural dual nanofibril system from citrus fiber and glycyrrhizic acid

The natural dual nanofibril system consisting of the rigid semicrystalline nanofibrils disintegrated from citrus fiber (CF) and soft semiflexible nanofibrils self-assembled from glycyrrhizic acid (GA) has been recently shown to be effective structural building blocks for fabrication of emulsion gels. In this work, the effect of the CF nanofibrils prepared by different mechanical disintegration approaches (i.e., high-pressure microfluidization and hydrodynamic cavitation) on the interfibrillar CF-GA interactions and the subsequent formation and properties of emulsion gels were investigated, with the aim of evaluating the potential of the dual nanofibril-stabilized emulsion gels as templates for synthesizing all-natural edible oleogels. The obtained results demonstrate that compared to the cavitation, the high-pressure microfluidization is more capable of generating CF nanofibrils with a higher degree of nanofibrillation and individualization, thus forming a denser CF-GA gel network with higher viscoelasticity and structural stability due to the stronger multiple intrafibrillar and interfibrillar interactions. The emulsion gels stabilized by the dual nanofibril system are demonstrated to be an efficient template to fabricate solid-like oleogels, and the structural properties of the oleogels can be well tuned by the mechanical disintegration of CF and the GA nanofibril concentration. The prepared oleogels possess high oil loading capacity, dense network microstructure, superior rheological and large deformation compression performances, and satisfactory thermal stability, which is attributed to the compact and ordered CF-GA dual nanofibrillar network via multiple hydrogen-bonding interactions in the continuous phase as well as at the droplet surface. This study highlights the unique use of all-natural dual nanofibrils to develop oil structured soft materials for sustainable applications.

Impact of functional dietary fiber incorporation on the appearance and mechanical properties of extruded high moisture meat analogs.

The effect of including functional dietary fiber ingredients (FDFI) on the texture and structure of high moisture meat analog (HMMA) was examined in this study. The inclusion of FDFI in this application is hypothesized to act as a label-friendly texture modifier in HMMA while also boosting the product's dietary fiber content. Two inclusion rates (5% and 10% wt/wt) of four functionally unique FDFI ingredients (pea hull, citrus fiber, hydrocolloid oat bran, and powdered cellulose) were blended with wheat protein isolate. Each unique formulation was processed using a high-moisture twin-screw extrusion process at two different screw speeds (200 and 400rpm). The type of FDFI added affected the mechanical texture attributes (hardness, springiness, cohesiveness, and integrity index) and in-process behavior (torque and pressure) of the resulting HMMA far more than the inclusion rate or screw speed (p>0.05). The type of FDFI ingredient employed also had the largest qualitative effect on the visual appearance of the resulting HMMA. These observed quality changes correlated well with the physicochemical and structure-function properties of the FDFI ingredients, especially with water-holding and absorption capacities. The incorporation of FDFI is a viable means of modulating HMMA texture and improving the holistic nutrition of these products. PRACTICAL APPLICATION: Adding highly functional, dietary fiber-rich ingredients to processed foods is a viable strategy for improving the nutritional and textural quality of these foods. The results of this study imply that these fibers can be added to meat analogs at nutritionally relevant rates, and the texture of the resulting product can be tailored based on the functional properties of the ingredients deployed.

Evaluating how citrus fiber affects the cell structure and functions of starch-based foam

This work used a proper content of citrus fiber (10 wt% ∼ 30 wt%, dry starch base) to improve the cell structures and functions of starch foam. The insoluble fiber promoted cell nucleation in the starch melt, whereas the soluble pectin improved the starch matrix's strength by forming ester bonding with starches as confirmed by FTIR results. This effectively modified the starch foaming process and endowed the obtained foams with an increased cell density (from 83.37 to 123.44 cell/cm3×104) and a reduced foam density (from 0.457 to 0.142 g/cm3). The foam containing 20 wt% citrus fiber exhibited the highest expansion ratio of 5.20. Due to the improved structures and the tortuous path effect of cellulose crystals, the prepared foams significantly presented a strengthened compression performance and improved moisture resistance. Meanwhile, the fiber-loaded foams displayed a high free radical-scavenging activity (60.30 % ∼ 85.75 %), showing good antioxidant activity. It is therefore believed that this study could provide a facile and green way for producing starch-based foams with desirable functions.

Optimization of citrus fiber-enriched vegan cream cheese alternative and its influence on chemical, physical, and sensory properties.

Dairy product alternatives have increased in recent years as a result of medical prescriptions or personal preferences. The main purpose of the present study was to optimize vegan-based cream cheese formulation added with citrus fiber considering the textural and physicochemical properties of the samples. The physicochemical (pH value, water activity, and color), texture, microstructure, and sensory properties of manufactured vegan-based cream cheese were characterized and compared to those of a commercial one. Three optimized products were produced, according to the textural properties. The addition of citrus fiber did not affect the pH and water activity values of the cheese samples significantly. Although citrus fiber had an effect on the color values of the samples, a significant difference in the sensory scores was not recorded by the panelists. The sample having 1.21% citrus fiber (A) showed a hardness value similar to that of control sample and it received high sensory appreciation. The sample added with 1.41% citrus fiber (B) was scored high by the panelists, with no significant difference compared to commercial cream cheese, even though it showed high hardness. According to the results of the current research, vegan-based cream cheese can be produced as a promising food as a new alternative to milk and dairy products.

Methylcellulose replacement with different enzymatically treated plant fibres as a binder in the production of plant-based meat patties

Texturised vegetable protein (TVP) is a sustainable and economical base for plant-based meat patties but requires binders to create an emulsified gel and hold the patty structure together. This study evaluated the physicochemical and sensory attributes of TVP patties incorporated with three different enzymatically-treated plant fibres i.e., pea (EPF), citrus (ECF) or apple (EAF) as a binder compared to positive control (methylcellulose, MC) and negative control (no binder, NC). All the patties with plant fibres had similar water-holding capacity compared to the MC. EAF exhibited the least fluid release and uniform surface, while ECF demonstrated the least cooking loss and shrinkage, uniform surface, hard texture, better cohesiveness, gumminess and chewiness compared to other samples. All the plant fibre-incorporated patties scored similarly for taste, texture, juiciness and overall acceptability compared to the positive control. The agglomerative hierarchical clustering revealed that the EPF had similar characteristics to the MC but the principal component analysis indicated that citrus fibre was a superior binder to pea fibre, therefore it could be used to replace methylcellulose for plant-based meat patties. Future research should explore more variations in plant-based binders to optimise the performance and sensory attributes of different types of texturised vegetable protein-based meat analogues.

ẢNH HƯỞNG CỦA BÍ ĐỎ VÀ KHOAI LANG ĐỎ ĐẾN CÁC TÍNH CHẤT HÓA LÝ VÀ CẢM QUAN CỦA KEM TƯƠI THỰC VẬT

With the rise in healthy diets and growing concerns about the environment and health, plant-based ice cream has become attractive to those who want to avoid animal products, food synthetic preservatives and additives. Recently, carbohydrates have been used as stabilizers to create gel structures and retain large amounts of free water in the food system. This study aimed to investigate the impact of pumpkin (PP), red sweet potato (SP), and their mixture on the physicochemical properties and sensory acceptance of plant-based ice cream prepared with a base of liquid obtained during the cooking of Lima beans (called aquafaba) and coconut milk. The recipe for the fresh plant-based ice cream mixture (% wt. of aquafaba) was as follows: sugar 20%; citrus fiber 1%; coconut milk powder 12%; coconut oil 6%; vanilla 0.6%. Four different formulas, which included the addition of 35% of PP (PP35), 35% of SP (SP35) and 35% of a mixture (M35) of PP and SP in a 1:1 ratio (by wt.), and a control sample (CS) with no addition were examined for cream viscosity, overrun (OR), water holding capacity (WHC), texture properties, melting rate and sensory evaluation. The results showed that, due to the advantages of both PP and SP, the ice cream M35 had the lowest melting rate with the dripping loss significantly reduced by 43-45% (%wt.) compared to PP35 and SP35. Besides, the sensory evaluation score of M35 was the highest, so M35 was considered the optimal supplement formula. This study contributes to the use of natural emulsion stabilizers in plant-based ice cream.

Modification, biological activity, applications, and future trends of citrus fiber as a functional component: A comprehensive review

Citrus fiber, a by-product of citrus processing that has significant nutritional and bioactive properties, has gained attention as a promising raw material with extensive developmental potential in the food, pharmaceutical, and feed industries. However, the lack of in-depth understanding regarding citrus fiber, including its structure, modification, mechanism of action, and potential applications is holding back its development and utilization in functional foods and drugs. This review explores the status of extraction methods and modifications applied to citrus fiber to augment its health benefits. With the aim of introducing readers to the potential health benefits of citrus fibers, we have placed special emphasis on their regulatory mechanisms in the context of various conditions, including type 2 diabetes mellitus, cardiovascular disease, obesity, and cancer. Furthermore, this review highlights the applications and prospects of citrus fiber, aiming to provide a theoretical basis for the utilization and exploration of this valuable resource.

A composite gel formed by konjac glucomannan together with Nano-CF obtained by FeCl3-citric acid hydrolysis as a potential fat substitute

This study aims to fabricate composite gels using nano citrus fiber (Nano-CF) derived from the hydrolysis process of citric acid (CA) with FeCl3, with a simultaneous exploration of its potential as an substitute to fats. Investigation of varying FeCl3 concentrations (0.01 to 0.03 mmol/g of CA) revealed a significant enhancement in the water-holding and oil-retention capacity of the Nano-CF. The meticulous synthesis of the composite gels involved integrating nano citrus fibers with konjac glucomannan (KGM) through high-speed shearing, followed by a comprehensive evaluation of its microstructure and physicochemical attributes. Increasing the Nano-CF concentration within the gels led to a synergistic interaction with KGM, resulting in enhanced viscosity, improved thermal stability, and restricted water molecule mobility within the system. The gels initially displayed reduced firmness, resilience, and adhesive characteristics, followed by subsequent improvement. When the ratio of Nano-CF to KGM was 0.5:1, the composite gels exhibited texture parameters, viscosity, and viscoelastic stability comparable to whipped animal cream formulations. These findings provide a new idea for the application of Nano-CF/KGM composite gels in whipped cream.

Enhancing water retention and mechanisms of citrus and soya bean dietary fibres in pre-fermented frozen dough

In recent years, the production of prepared and frozen foods has increased with economic development. However, during freezing, moisture migration forms ice crystals that damage food structure and reduce quality. This study investigates moisture migration changes in pre-fermented dough during frozen storage and effectiveness of Citrus fibre (CF) and Soya dietary fibre (SDF) on quality improvement. Pre-fermented frozen dough properties were evaluated at different freezing storage days with CF and SDF. Results showed frozen storage reduced water retention, converting deeply bound water to weakly bound and free water. Freezable water content increased significantly from 53% (fresh) to 56.95% (60d-control), forming disruptive ice crystals in gluten protein structure. SDF had superior water flow restriction compared to CF, preventing large ice crystal accumulation, enhancing water-holding capacity, and maintaining gluten protein structure. These findings lay a theoretical foundation for improving quality and industrial applications of pre-fermented frozen dough.

Fabrication and characterisation of Pickering emulsion‐based oleogel stabilised by citrus fibre and whey protein isolate colloidal complex: application in cookie formulation

SummaryIn this study, the oleogel was produced by Pickering emulsion‐based method by using citrus fibre (CF)‐whey protein isolate (WPI) colloidal complex. The obtained oleogels were characterised by rheological and textural properties, and then the oleogels were used in cookies as an alternative to palm oil. The four oleogels (1% to 5%) were fabricated using a CF‐10% WPI complex. Shear thinning rheological behaviour was observed in all emulsion and oleogel samples. The G values were greater than the G values, indicating that solid‐like behaviour dominated in all emulsion and oleogel samples. All oleogel samples had a higher than 90% oil‐holding capacity. The visual appearance of 3% CF‐10% WPI and 5% CF‐10% WPI showed no surface oil, and more integrity structure means that could well trap oil in a gel matrix. Increasing CF% concentration reduced oil droplets and created a more compact structure, particularly at 3% and 5% CF‐10% WPI. An increase in CF concentration from 2% to 5% led to an increase in the hardness value of the dried products and cookies that CF formed a 3D network structure with binds liquid oil. The oxidative stability showed that no significant changes were found between the 3% CF‐10% WPI and palm cookies (P < 0.05). Cookies containing oleogels with a 3% CF content exhibited a visual resemblance to this trait, suggesting a colour appearance that closely resembled cookies made with palm oil. The incorporation of oleogels into the cookie recipe proved to be an effective substitute for palm oil. CF‐10% WPI oleogels show promise for use in cookie preparation as a replacement for palm oil, offering potential as substitutes for saturated and trans fats in food products.

Development and rheological modeling of dietary fiber and policosanol plant-based bigels for potential food applications

Bigels are composite materials made by two phases with different polarities (i.e., an oleogel and a hydrogel) mixed between them without the addition of emulsifiers. Owing to their versatile rheological properties, they can be used for designing new products for food industry, or for cosmetics and pharmaceutical applications. In the past, different models have been proposed to relate their rheological properties to single phases characteristics and volume fraction. This paper proposes the rheological characterization and modeling of bigels prepared with citrus fiber particle gels (as the aqueous phase) and policosanol-based oleogels by investigating the effects of the ratio between rheological properties of phases and of the dispersed phase volume fraction. Both components (i.e., citrus fiber and policosanol) exhibit interesting properties for preparing plant-based healthy foodstuffs. Rheological characterization was carried out revealing that O/W bigels were formed at low fractions of oleogel added to gelled suspension whereas, at higher fractions, a transition through a matrix-in-matrix systems and, finally, a phase inversion occurred. The trend of phase angle at 1 Hz with oleogel volume fraction was used as a criterion to highlight the phase transition, as confirmed by confocal microscopy. Two models were proposed for predicting the rheological behavior of samples with both phase arrangements.

Citrus waste fibres for natural cosmetic and bioplastic packaging

In this work new biocomposite materials from wasted citrus peels has been validated for a value-added packaging and novel cosmetic products. Specifically, extracted natural fibres and dehydrated pulp from citrus fruit were combined with polylactic acid and other additives as materials for the production of bio-based packaging jars and cosmetic products. For the composition of the packaging an orange powder (dehydrated wastes) was found to be the best performing, while orange comminute, which results from milling the orange peel, was most suitable for composition of the cosmetic formulations. Polylactic acid was compounded with citrus fibres by up to 25 wt.% by twin screw extrusion and processed via injection moulding, one of the most widespread processing technologies for producing rigid packaging containers. Composites were characterized, defining their mechanical, morphological and thermal properties. Validation of packaging thermostability performance was performed by Heat deflection temperature in compliance to ISO75 and VICAT softening temperature in accordance with ISO306. Compatibility tests of packaging demonstrators with newly formulated cosmetic products has been investigated as well. An accelerated compatibility test of the cosmetic jars with water and oil-based simulants was performed at ambient temperature, -5 °C, and at 45 °C. The results indicated that new cosmetic packaging are not consistent with water-based cosmetic formulations but are compatible with products based on natural oils. While the price of these products is generally higher than those using conventional plastics, they are competitive for premium cosmetic brands.

Potential of Modification of Techno-Functional Properties and Structural Characteristics of Citrus, Apple, Oat, and Pea Dietary Fiber by High-Intensity Ultrasound.

Plant fibers are rich in dietary fiber and micronutrients but often exhibit poor functionality. Ultrasonication can affect the particle size of plant fiber, thereby influencing other techno-functional properties. Therefore, this study aimed to investigate the effects of high-intensity ultrasound on citrus, apple, oat, and pea fiber. Initially, solutions containing 1 wt% of plant fiber were homogenized using ultrasonication (amplitude 116 µm, t = 150 s, energy density = 225 kJ/L, P¯ = 325 W). Due to cavitation effects induced by ultrasound, differences in particle size and a shift in the ratio of insoluble and alcohol-insoluble fractions for dietary fiber were observed. Additionally, viscosities for citrus and apple fiber increased from 1.4 Pa·s to 84.4 Pa·s and from 1.34 Pa·s to 31.7 Pa·s, respectively, at shear rates of 100 1s. This was attributed to observed differences in the microstructure. Freeze-dried samples of purified citrus and apple fiber revealed thin and nearly transparent layers, possibly contributing to enhanced water binding capacity and, therefore, increased viscosity. Water binding capacity for citrus fiber increased from 18.2 g/g to 41.8 g/g, and a 40% increase was observed for apple fiber. Finally, ultrasound demonstrated itself be an effective technology for modifying the techno-functional properties of plant fiber, such as water binding capacity.

All-Natural, Plant-Based Nanofibrils from Citrus Fiber and Glycyrrhizic Acid for Stabilization of Edible Emulsion Gels

All-Natural, Plant-Based Nanofibrils from Citrus Fiber and Glycyrrhizic Acid for Stabilization of Edible Emulsion Gels