Dietary fiber extraction from citrus peel pomace: Yield optimization and evaluation of its functionality, rheological behavior, and microstructure properties

Preparation and Characterization of Soluble Dietary Fiber Edible Packaging Films Reinforced by Nanocellulose from Navel Orange Peel Pomace

The packaging problem with petroleum-based synthetic polymers prompts the development of edible packaging films. The high value-added reuse of navel orange peel pomace, which is rich in bioactive compounds, merited more considerations. Herein, nanocellulose (ONCC) and soluble dietary fiber (OSDF) from navel orange peel pomace are firstly used to prepare dietary fiber-based edible packaging films using a simple physical blend method, and the impact of ONCC on the film's properties is analyzed. Adopting three methods in a step-by-step approach to find the best formula for edible packaging films. The results show that dietary-fiber-based edible packaging films with 4 wt.% ONCC form a network structure, and their crystallinity, maximum pyrolysis temperature, and melting temperature are improved. What's more, dietary-fiber-based edible packaging films have a wide range of potential uses in edible packaging.

Composite optimization and characterization of dietary fiber-based edible packaging film reinforced by nanocellulose from grapefruit peel pomace

The development of edible packaging films was motivated due to resource waste and environmental damage caused by chemically produced plastic packaging. The development of edible packaging film based on grapefruit peel pomace dietary fiber has significant technological and functional potential because grapefruit processing waste is a potential source of high-quality dietary fiber. In this study, the first successful development of an edible packaging film based on dietary fiber using grapefruit soluble dietary fiber (GSDF) from grapefruit peel pomace as a substrate and nanocellulose (GNCC) as a filler was developed. Principal component analysis, membership function synthesis, and response surface methods were used to determine the optimal process to prepare the edible packaging films, and the impact of GNCC on this material was analyzed. The results showed that the overall performance score of the edible packaging film with 1 wt% GNCC was 0.764. The maximum pyrolysis temperature increased from 226.36 °C to 227.10 °C, the melting temperature (Tm) increased by 5.54 °C, the crystallinity increased by 2.95 %. The film solution exhibited non-Newtonian characteristics and a solid-like property. Our results showed that the edible packaging film developed from grapefruit peel pomace and dietary fiber could have several potential applications in the food packaging field.

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.