Concentrates from citrus juice obtained by crossflow microfiltration: Guidance of the process considering carotenoid bioaccessibility

Functional compounds in tropical fruit processing by-products and intrinsic factors affecting their composition: A review

Tropical fruits, highly demanded in the food industry, generate a considerable amount of waste during processing. These traditionally discarded by-products, such as peels, seeds and pomace, are rich in bioactive compounds, natural molecules that have beneficial properties for human health, as they participate in various metabolic processes in the organism. Among the most prominent compounds are flavonoids, carotenoids, phenolic compounds, tannins and vitamin C. Beyond their health benefits, these compounds have significant industrial value and are widely used in the textile, pharmaceutical, cosmetic, biotechnological and food fields, in the latter especially as preservatives, additives, colorants and others. This review explores the main bioactive compounds found in fruit by-products, highlighting their functional relevance and analyzing the intrinsic or fruit-derived factors that influence the composition of these compounds, such as the type of by-product (peels, seeds, bagasse, pomace), the variety of fruit, and the state of maturity at the time of processing. In addition, the extraction methods used to obtain these compounds are addressed, differentiating between conventional techniques, such as solvent extraction, and emerging methods, such as ultrasound-assisted extraction and supercritical fluid extraction, which offer advantages in terms of efficiency and sustainability. The diversity of bioactive compounds and their potential application in various industries highlight the importance of ongoing research in this field. It is necessary to further study the factors that influence the composition of these compounds, as well as the development of more efficient and sustainable extraction methods. These advances will not only add value to food industry waste, but will also contribute to the development of natural products with health benefits.

Coupling Low-Frequency Ultrasound to a Crossflow Microfiltration Pilot: Effect of Ultrasonic Pulse Application on Sono-Microfiltration of Jackfruit Juice

To reduce membrane fouling during the processing of highly pulpy fruit juices into clarified beverages, a crossflow Sono-Microfiltration (SMF) system was employed, strategically equipped with an ultrasonic probe for the direct application of low-frequency ultrasound (LFUS) to the juice just before the entrance to the ceramic membrane. Operating conditions were standardized, and the application of LFUS pulses in both corrective and preventive modes was investigated. The effect of SMF on the physicochemical properties and the total soluble phenol (TSP) content of the clarified juice was also evaluated. The distance of ultrasonic energy irradiation guided the selection of the LFUS probe. Amplitude conditions and ultrasonic pulses were more effective in the preventive mode and did not cause membrane damage, reducing the operation time of jackfruit juice by up to 50% and increasing permeability by up to 81%. The SMF did not alter the physicochemical parameters of the clarified juice, and the measured LFUS energy ranges did not affect the TSP concentration during the process. This study is the first to apply LFUS directly to the feed stream in a pilot-scale crossflow microfiltration system to reduce the fouling of ceramic membranes and maintain bioactive compounds in jackfruit juice.

Application of Emerging Techniques in Reduction of the Sugar Content of Fruit Juice: Current Challenges and Future Perspectives

In light of the growing interest in products with reduced sugar content, there is a need to consider reducing the natural sugar concentration in juices while preserving the initial concentration of nutritional compounds. This paper reviewed the current state of knowledge related to mixing juices, membrane processes, and enzymatic processes in producing fruit juices with reduced concentrations of sugars. The limitations and challenges of these methods are also reviewed, including the losses of nutritional ingredients in membrane processes and the emergence of side products in enzymatic processes. As the existing methods have limitations, the review also identifies areas that require further improvements and technological innovations.

Impact of crossflow microfiltration on aroma and sensory profiles of a potential functional citrus-based food

BACKGROUND

Citrus juices can be cold-concentrated by crossflow microfiltration (CMF) in order to obtain functional foods enriched in carotenoids, flavonoids and pectins. The work aimed to characterize the organoleptic quality of this type of micronutrient-dense foods through their aroma profile and sensory analysis. Two citrus concentrates with and without a diafiltration step were compared.

RESULTS

Both citrus products were very different, linked to aroma compound, sugar and organic acid contents. Due to its sugar/acidity balance and its better aromatic profile responsible for the citrus-floral flavour, the concentrate without diafiltration was preferred by the sensory panel. Thanks to a simple transfer model, we showed that retention of volatiles clearly varied from one aroma compound to another. The terpene hydrocarbons were the most retained by the membrane during CMF, probably because they were strongly associated with insoluble solids by adsorption.

CONCLUSION

Even though the process modified their organoleptic profiles, both citrus-based products were well rated and can be consumed directly as pleasant functional drinks. © 2022 Society of Chemical Industry.