Stability of Flavonoid, Carotenoid, Soluble Sugar and Vitamin C in 'Cara Cara' Juice during Storage

The Browning Properties, Antioxidant Activity, and α-Glucosidase Inhibitory Improvement of Aged Oranges (Citrus sinensis)

Oranges contain many natural active chemicals, organic acids, and polysaccharides. Aging processing is commonly used to modify the color, quality, functional components, and stability of fruits. This study assesses the preparation of aging black oranges using various pre-treatments and solid fermentation. Oranges were aged for six weeks in fresh, non-blanching, blanching, and hot air-assisted aging cycle (AA) groups. The oranges' shrinkage ratio, color difference values, and soluble solids content changed significantly (p < 0.05). Principal component analysis indicated that aging fermentation treatment accelerated glycolysis and increased the ratio of reducing sugars. The enhanced browning can be associated with the oxidation of ascorbic acid (0.66-0.47 mg/g) and the formation of 5-hydroxymethylfurfural (5-HMF) (0.09 mg/g). Furthermore, the presence of free polyphenols led to an increase in the total polyphenol and total flavonoid content. It also had a synergistic effect with 5-HMF in increasing the 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging capacity and ferric ion-reducing antioxidant power (p < 0.05). AA had superior α-glucosidase inhibitory ability increasing from 67.31 to 80.48%. It also reduced the development time by 33%. Therefore, aging technology can enhance the bioactive compounds in oranges and provide a reference for future whole-fruit aging fermentation and health product creation.

Engineered living materials for the conversion of a low-cost food-grade precursor to a high-value flavonoid

Microbial biofactories allow the upscaled production of high-value compounds in biotechnological processes. This is particularly advantageous for compounds like flavonoids that promote better health through their antioxidant, anti-bacterial, anti-cancer and other beneficial effects but are produced in small quantities in their natural plant-based hosts. Bacteria like E. coli have been genetically modified with enzyme cascades to produce flavonoids like naringenin and pinocembrin from coumaric or cinnamic acid. Despite advancements in yield optimization, the production of these compounds still involves high costs associated with their biosynthesis, purification, storage and transport. An alternative production strategy could involve the direct delivery of the microbial biofactories to the body. In such a strategy, ensuring biocontainment of the engineered microbes in the body and controlling production rates are major challenges. In this study, these two aspects are addressed by developing engineered living materials (ELMs) consisting of probiotic microbial biofactories encapsulated in biocompatible hydrogels. Engineered probiotic E. coli Nissle 1917 able to efficiently convert cinnamic acid into pinocembrin were encapsulated in poly(vinyl alcohol)-based hydrogels. The biofactories are contained in the hydrogels for a month and remain metabolically active during this time. Control over production levels is achieved by the containment inside the material, which regulates bacteria growth, and by the amount of cinnamic acid in the medium.

Assessment of the stability of compounds belonging to neglected phenolic classes and flavonoid sub-classes using reaction kinetic modeling

Phenolic compounds are known to degrade and/or undergo changes during food production and storage. Reaction kinetic modeling is generally used to define kinetic parameters of a food system and predict changes during thermal processing and storage. Data for phenolic acids and flavonoids, such as anthocyanins and flavan-3-ols, have been reviewed in detail, but the flavonoid sub-classes, dihydrochalcones and flavanones, have been mostly neglected. Other neglected phenolic classes are xanthones and benzophenones. The stability of these types of compounds is important as they are present in fruits and exposed to heat when processed into juice and jam. Other sources of the compounds are herbal teas, which are also subjected to thermal processing, either during the primary processing of the plant material, or the production of extracts for use as food ingredients. The theoretical background is given to understand the review of literature on these classes/sub-classes. Results of research on kinetic modeling are discussed in detail, while research on compound stability without the application of reaction kinetic modeling is briefly mentioned to provide context. The studies discussed included those focusing on heating during the processing and storage of model solutions, liquid foods, plant material, dried extracts, and extracts formulated with other food ingredients.

Juices and By-Products of Red-Fleshed Sweet Oranges: Assessment of Bioactive and Nutritional Compounds

The content of nutrients and bioactive compounds, and antioxidant capacity were assessed in the juices from two red-fleshed oranges, Cara Cara and Kirkwood, and compared with that of a standard Navel orange. Two juice extraction procedures, hand-squeezing and industrial, and two treatments, pasteurization (85 °C/30 s) and high-pressure homogenization (HPH, 150 MPa/55 °C/1 min), were evaluated. For most of the nutrients and bioactive compounds, the hand and industrial juice squeezing rendered similar extraction efficiency. Individual composition of carotenoids in the juices were differentially affected by the extraction procedure and the treatments, but the red-fleshed orange juices contained between 3- to 6-times higher total carotenoids than the standard Navel juices, being phytoene and phytofluene the main carotenoids. The industrial and treated juices of both red-fleshed oranges contained 20-30% higher amounts of tocopherols but about 20% lower levels of vitamin C than Navel juices. Navel juices exhibited higher hydrophilic antioxidant capacity, while the red-fleshed orange juices showed an improved lipophilic antioxidant capacity. The main distinctive characteristic of the industrial juice by-product of the red-fleshed oranges was a higher content of carotenoids (×10) and singlet oxygen antioxidant capacity (×1.5-2) than the Navel by-product.

Discoloration Investigations of Yellow Lantern Pepper Sauce (Capsicum chinense Jacq.) Fermented by Lactobacillus plantarum: Effect of Carotenoids and Physiochemical Indices

Color is one of the important indicators affecting the quality of fermented pepper sauces, and it is closely related to carotenoid composition. This study systematically analyzed the changes in carotenoids and related physiochemical indices during the fermentation of yellow lantern pepper sauce. The CIELab color values indicated that L* and C* displayed a significant decreasing trend during fermentation. After 35 days of fermentation, the total carotenoid content significantly reduced from 3446.36 to 1556.50 μg/g DW (p < 0.05), and the degradation rate was 54.84%. Among them, the total content of carotene decreased by 56.03% during fermentation, whereas the degradation rate of xanthophylls and their esters was 44.47%. According to correlation analysis, violaxanthin myristate and lutein played a pivotal role in L*, a *, b *, chroma (C*), and yellowness index (YI). Moreover, PCA analysis indicated that lactic acid and acetic acid were the important qualities affecting the stability of pigment in fermented yellow lantern pepper sauce, which might also be the inducement of the color change. This work gives additional information concerning the discoloration of yellow lantern pepper sauce during fermentation and provides theory evidence regulating and improving the sensory qualities of yellow lantern pepper sauce.

The Health Benefits of the Bioactive Compounds in Foods

The health benefits of consuming certain foods have been commonly known since ancient times [...].

Quality Attributes of Cryoconcentrated Calafate (Berberis microphylla) Juice during Refrigerated Storage

This study aimed to evaluate the potential of centrifugal block cryoconcentration (CBCC) at three cycles applied to fresh calafate juice. The fresh juice and cryoconcentrate at each cycle were stored for five weeks at 4 °C and quality attributes were analyzed every 7 days. CBCC had significant effects in the calafate juice, since in the last cycle, the cryoconcentrate reached a high value of total soluble solids (TSS, ≈42 °Brix), with final attractive color, and an increase of approximately 2.5, 5.2, 5.1, 4.0 and 5.3 times in relation to the fresh juice values, for total bioactive compounds (TBC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC), respectively. However, at 35 days under storage, these values decreased by 5%, 13%, 15%, 19%, 24% and 27%, for TSS, TBC, DPPH, ABTS, FRAP and ORAC, respectively. Additionally, until the day 14, the panelists indicated a good acceptability of the reconstituted cryoconcentrate. Therefore, CBCC can be considered a novel and viable technology for the preservation of quality attributes from fresh calafate juice with interesting food applications of the cryoconcentrates due to their high stability during storage time in comparison to the fresh juice.