Total Carotenoid Content Research Articles

Gluten-Free Sweet Potato Flour: Effect of Drying Method and Variety on the Quality and Bioactivity

Sweet potato (Ipomoea batatas (L.) Lam.) is a nutrient-dense crop rich in fibre, minerals, and antioxidant compounds, including carotenoids and phenolic compounds, such as anthocyanins. Dehydrating sweet potato (SP) for flour production enhances its value and produces shelf-stable, health-promoting food products. This study investigated the effects of hot-air drying (HAD: 75 °C/20 h) and freeze-drying (FD: −41–30 °C/70 h) on the bioactive composition of flours from three SP varieties: Bonita (white-fleshed), Bellevue (orange-fleshed), and NP1648 (purple-fleshed). Key assessments included the total phenolic content (TPC), the total carotenoid content (TCC), and the total anthocyanin content (TAC) and the antioxidant activity (DPPH and FRAP). The results revealed distinct raw materials’ bioactive profiles: Bellevue was rich in TCC (49.3 mg of β-carotene/100 g db), NP1648 showed elevated TAC (27.3 mg of cyanidin-3-glucoside/100 g db), and Bonita exhibited minimal content of bioactive compounds. Both drying methods yielded significant losses of bioactive compounds, with the TPC decreasing by over 60%, while TAC and TCC losses did not exceed 32%, revealing higher stability. Multivariate analysis indicated that the variety significantly influenced the bioactive profiles more than the drying method. The interaction between carotenoids and anthocyanins and the SP fibrous composition likely contributed to their stability during drying, indicating that FD showed no advantages over HAD. The appealing colours and high antioxidant content of Bellevue and NP1648 flours suggest their potential as ingredients for enhancing foods’ bioactivity and sensory acceptance.

Lighting Patterns Regulate Flowering and Improve the Energy Use Efficiency of Calendula Cultivated in Plant Factories with Artificial Lighting

Calendula is an edible flower with highly beneficial bioactive compounds for human health. Environmental factors such as light influence flower yield and quality. Calendula is cultivated under controlled environments in plant factories with artificial lighting (PFALs), which enhance its productivity. However, electricity is the main operating cost, with fees based on the time of use in some countries. This study aimed to investigate the effects of lighting patterns on calendula growth and yield. Two varieties of calendula seedlings were cultivated in a PFAL and subjected to six different lighting patterns, i.e., 6 h/6 h, 12 h/12 h, 6 h/2 h, and 18 h/6 h (light/dark) and two continuous lighting patterns with varying light intensities (24 h-200 and 24 h-400). The results indicated that plants cultivated under the 6 h/2 h, 18 h/6 h, 24 h-200, and 24 h-400 conditions showed a more rapid appearance of the first flower bud than those cultivated under the 6 h/6 h and 12 h/12 h conditions. The number of flowers and the fresh and dried weights tended to increase with a longer photoperiod. Interestingly, the total carotenoid content (TCC) of “Citrus Orange” increased under 6 h/6 h and 12 h/12 h conditions compared with the others. For “Orange Gem”, continuous lighting (24 h) increased the total phenolic content (TPC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity in flowers compared with the 6 h/6 h 12 h/12 h, and 6 h/2 h treatments. The energy use efficiency (EUE) under the 24 h-200 condition was the highest in terms of flower yield and secondary metabolite production. These results suggest that lighting patterns can be used to modulate the growth and flowering of calendula and to maximize EUE.

Biodegradable active films based on Chlorella biomass and cellulose nanocrystals isolated from hemp stalk fibers

Cellulose nanocrystals (CNC)-reinforced biopolymers have emerged as a widely embraced approach for enhancing the characteristics of biopolymers due to their exceptional properties. Biocomposite (Chl-CNC) films were fabricated by blending Chlorella biomass and varying concentrations of CNCs via a solution casting technique. CNCs were effectively isolated from hemp stalk fibers, as confirmed by structural, surface, thermal, and morphological analysis. The crystallinity of films increased by CNC incorporation, which was confirmed by the XRD. The presence of molecular interactions between CNC and protein-rich Chlorella biomass was illustrated with the FTIR analysis. These interactions enhanced the physicochemical properties of the films. Further, films demonstrated a high level of soil biodegradation in the 42 days, while their total phenolic, chlorophyll, carotenoid contents, and antibacterial activity were unaffected by the incorporation of CNCs. The Chl-CNC films, regardless of CNC addition, indicated antimicrobial activity toward Escherichia coli but not Staphylococcus aureus. These results indicate that developed biobased and biodegradable Chl-CNC films could be highly beneficial in active food packaging applications.

Enhancement of ketocarotenoid production using the heterologous orange protein from Ipomoea batatas in indigenous microalga Ettlia sp.

Astaxanthin, one of the most powerful natural antioxidants, is used in high-value industries such as those of cosmetics, nutraceuticals, and food products derived from microalgae. In this study, Ettlia sp. mutants were generated by expressing two types of heterologous orange proteins, IbOr and IbOr-R96H, in which the 96th arginine of IbOr was substituted with histidine derived from Ipomoea batatas to enhance astaxanthin production. The Ett-IbOr-R96H mutant showed a 2.4-fold increase in β-carotene content compared to the wildtype (4.59 mg g−1DCW), reaching 10.82 mg g−1 under high-light conditions via two-phase cultivation. Under the stress treatment combination of high-light intensity and nitrogen deprivation, total carotenoid content increased to 17.24 mg L−1 and 21.94 mg L−1 in Ett-IbOr and Ett-IbOr-R96H, respectively. The astaxanthin and canthaxanthin contents in Ett-IbOr-R96H was 4.89 mg L−1 and 0.47 mg L−1, respectively, which were 1.8- and 1.5-fold higher, respectively, than those in Ett-IbOr. Additionally, photosynthetic efficiency (Fv/Fm) recovered in Ett-IbOr-R96H under dual-stress conditions compared to the wildtype while reactive oxygen species levels decreased throughout the cultivation period. Our findings suggest that the heterologous IbOr expression in Ettlia sp. may be an effective approach for enhancing the production of ketocarotenoids and improving stress resistance for industrial applications.

Oleogels based on carotenoid-rich microbial oil produced by R. mucilaginosa in agro-industrial by-products.

This study aimed to evaluate different methods of recovery of carotenoid-rich microbial oil (CRMO) produced by Rhodotorula mucilaginosa in renewable agro-industrial by-products to achieve oleogels based on CRMO and carnauba wax (CW). Among the oil extraction methods, Bligh and Dyer was selected since this system kept color stability. Extracted CRMO showed 41.1 µg g-1 of total carotenoid and lipid content of 23.8%. Oleogels based on CRMO or olive oil (control system) and CW at concentrations of 2.5, 5, 7.5, and 10% were characterized and their potential application to food systems was highlighted. This study is one of the first to describe production of oleogel based on CRMO. Its results contribute to its potential as a fat replacer. This novel oleogel may meet worldwide demands to reduce trans fatty acids in foods and act as a protective system of bioactive biocompounds.

Targeted metabolomics- and transcriptomics-based investigation of carotenoid pigmentation in Phalaenopsis-Type Dendrobium hybrids

Phalaenopsis-type Dendrobium hybrids (Den-Phals) stands out as globally popular tropical orchids. Carotenoids are crucial colored phytochemicals in flowers. The coloration mechanism of carotenoids in Den-Phals flowers were investigated through targeted metabolome and transcriptome analyses. In total, 48 carotenoids were detected from 11 Den-Phals. The composition and content of carotenoids varied among these cultivars and in the different parts of the same flowers. Lutein, which improves human visual performance, had the largest content in all the samples, with an average of 52.46%, and the highest value reached 79.45%. The top 10 carotenoids, including lutein, β-carotene, neoxanthin, iolaxanthin, (E/Z)-phytoene, zeaxanthin, antheraxanthin, α-cryptoxanthin, β-cryptoxanthin, and α-carotene, collectively constituted 90% of the total carotenoids content. Among them, β-carotene, rather than lutein, was correlated with the yellow hue of floral color and was considered a key pigment. Furthermore, transcriptome sequencing of two cultivars with significant difference in carotenoid contents inferred the carotenoid metabolic pathway in Den-Phals. Seven differentially expressed genes (DEGs) were isolated: phytoene synthase (PSY), carotenoid isomerase (CrtISO), ζ-carotene isomerase (Z-ISO), lycopene ε-cyclase (LCYE), β-carotene hydroxylase (BCH), zeaxanthin epoxidase (ZEP), and 9-cis-epoxycarotenoid dioxygenase (NCED). Among these, LCYE was deemed a crucial enzyme gene, as it appears to govern lutein or β-carotene accumulating, thereby influencing yellow coloration of Den-Phals. The results offer valuable understanding of the carotenoid metabolic pathway and provide new guidance for breeding Den-Phals cultivars having both ornamental and medicinal traits.

Physicochemical characteristics of sawo belanda (Pouteria Campechiana) flour with blanching process and drying techniques

Introduction: Sawo belanda fruit (Pouteria campechiana), a tropical fruit abundantly found in Southeast Asia, is highly productive and particularly thrives in the warm climates of Malaysia and Indonesia. However, the high fruit output of sawo belanda contrasts with its limited consumption in Indonesia. The process of converting sawo belanda into flour can significantly enhance its lifetime. The application of blanching methods and proper drying techniques can be a solution to avoid damage to the characteristics of the flour. This study aimed to determine the physicochemical characteristics of sawo belanda flour that has been treated with blanching and drying techniques. Methods: The parameters observed were moisture content (%), hygroscopicity (%), colour, antioxidant content (ppm), and carotenoid content (µg/g) with blanching and various drying techniques. Results: Microwave blanching and food dehydrator technique (C1) produced the best characteristics: moisture content of 7.82%, hygroscopicity of 8.04%, colour values of L* 84.0, a* 8.22, and b* 50.5, as well as functional characteristics including antioxidant content of 142 ppm and carotenoid content of 92.4 µg/g. Conclusion: Sawo belanda with C1 treatment had a significant impact on the water content, hygroscopicity, colour, antioxidant and total carotenoid contents of sawo belanda flour. The antioxidant content and incredibly high carotenoid content grant the sawo belanda flour an additional functional value when added to food ingredients.

QUANTITATIVE ANALYSIS OF NUTRITIONAL AND BIOACTIVE COMPOUNDS IN FRUITS OF KIWANO (CUCUMIS METULIFERUS E. MEY) TEMPUS CULTIVAR

Locally-grown kiwano fruits, Tempus cultivar, were evaluated for their content in some main classes of nutritional organic compounds. With 448/98 mg/kg DW (pulp/peel) total carotenoid content was average when compared to other Cucurbitaceae. Among identifiable carotenoids, lycopene was the only one in notable amounts, in peel (12% of total carotenoids). With 51,751/37,624 mg/kg, total phenolic inventory was extremely rich. Flavonoids were clearly dominant (78/49%). Hydroxycinnamic acids were found in significant proportions (11/27%). Fruit pulp also showed some amounts of tannins (5.9%) and stilbenes (2%), while coumarins were found in low amounts. Ascorbic acid was abundant, 20,140 mg/kg in pulp and 7,689 mg/kg in peel. Soluble sugars were 15,915 /6,634 mg/kg while lipids were 5,556 /2,721 mg/kg.

Integrative Analysis of Metabolome and Transcriptome Profiles to Evaluate the Response Mechanisms of Carex adrienii to Shade Conditions

Carex is a type of herbaceous plant with high application value, playing an important role in the urban periphery. Due to its unique morphology and ecological characteristics, Carex is widely used in various fields, such as landscaping, ecological restoration and soil and water conservation, which help to maintain the balance of the ecosystem. In order to explore the potential molecular mechanisms of shade tolerance in Carex, transcriptome and metabolome sequencing were performed on the leaves of the shade = tolerant species Carex adrienii E. G. Camus. under 80% shade and no shade conditions. Compared to control group (CK), the total chlorophyll, chlorophyll a, chlorophyll b and total carotenoid content in the C. adrienii leaves of the shading treatment were significantly upregulated. The antioxidant enzyme activity of the leaves, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), were also remarkably upregulated in the shading treatment groups. In addition, the net photosynthesis rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of the leaves were reduced, and the intercellular CO2 concentration (Ci) of the leaves was increased under shade. The transcriptome identified 5056 differentially expressed genes (DEGs) and the metabolome identified 889 differential accumulated metabolites (DAMs) in three treated samples. The integrated transcriptomic and metabolomic analyses results showed that the DEGs and DAMs were enriched in photosynthesis, plant hormone signal transduction and flavonoid biosynthesis synthesis pathways. The ABA content of the C. adrienii leaves was significantly increased under shade. Therefore, the shading conditions led to changes in chlorophyll and abscisic acid (ABA), as well as the accumulation of flavonoids in C. adrienii, both of which were achieved by regulating genes involved in photosynthesis, plant hormone signal transduction and flavonoid biosynthesis molecular networks. Our results provide new knowledge for the molecular response and metabolic regulatory mechanisms of C. adrienii to shade stress, and valuable genetic resources for C. adrienii shade tolerance molecular breeding.

Comparative transcriptome and metabolomic analysis reveal key genes and mechanisms responsible for the dark-green leaf color of a strawberry mutant

Photosynthesis is a source of energy for various types of plant life activities and is essential for plant growth and development. Consequently, the study of photosynthetic mechanisms has been a hot spot. Leaf color mutants has always been ideal materials for exploring the mechanisms of chlorophyll metabolism and photosynthesis. In this study, we identified a leaf color mutant of ‘Benihoppe’ strawberry in the field, which exhibited a darker green leaf color compared with the wild type. The content of total chlorophyll and carotenoid in the mutant leaves was elevated by 7.44–20.23% and 8.9–21.92%, respectively, compared with that of the wild type. Additionally, net photosynthetic rate in the mutant increased by 20.13%. Further transcriptome analysis showed that significant upregulation of genes such as GLK1, PPR, and MORF9 in the mutant leaves, which promoted chloroplast development. The expression levels of UROD, PPOC, PORA, CHLG, and CPOX were significantly upregulated during chlorophyll synthesis, while the expression levels of HCAR and CYP89A9 were significantly downregulated during chlorophyll degradation, thus leading to the accumulation of chlorophyll in mutant leaves. The upregulation of gene expression levels such as PetM, AtpD, PGK, and RPI4 during photosynthesis promoted multiple stages of light and dark reaction, thereby enhancing the photosynthetic capacity of the mutant. And the changes in metabolites such as monogalactosyl monoacylglycerol (MGMG), glucuronosyldiacylglycerol (GlcADG), raffinose, etc. also indicate that the mutant has metabolic differences in chloroplast composition and photosynthesis compared to ‘Benihoppe’. The above results not only deepen our understanding of the mechanism behind the dark-green leaf color in strawberry mutants but also provide potential genetic resources for cultivating strawberry varieties with enhanced photosynthetic capacity.

Seaweed Nutritional Value and Bioactive Properties: Insights from Ascophyllum nodosum, Palmaria palmata, and Chondrus crispus.

This study investigates the nutritional composition and bioactive properties of Palmaria palmata (dulse), Ascophyllum nodosum (knotted wrack), and Chondrus crispus (Irish moss). Understanding the nutritional values of these seaweeds is very important due to their potential health benefits, especially their antioxidant properties and cytotoxic activities, which point to their ability to inhibit cancer cell proliferation. Comprehensive analyses were conducted to assess protein content, amino acid composition, mineral profile, fatty acids, polyphenols, total carotenoids, antioxidant activity, and cytotoxicity against cervical (HeLa), and colon (HCT-116) cell lines. P. palmata exhibited the highest protein content, while C. crispus was richest in calcium, iron, manganese, and zinc. Amino acid analysis revealed C. crispus as being particularly high in essential and non-essential amino acids, including alanine, glutamic acid, and glycine. A. nodosum and C. crispus were rich in polyunsaturated fatty acids (PUFAs), notably eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). A. nodosum showed the highest total carotenoid content. Polyphenol analysis highlighted the presence of compounds such as p-coumaric acid, gallic acid, and p-hydroxybenzoic acid across the species. Both the ethanolic and hexane A. nodosum extracts demonstrated the strongest antioxidant potential in DPPH• and ABTS+ assays. The cytotoxicity evaluation revealed high anticancer activity of A. nodosum and C. crispus hexane extract against HeLa and HCT-116, though it employed cell cycle arrest and apoptosis. A. nodosum hexane extract exhibited moderate selective anticancer activity against HCT-116. These findings underscore the nutritional diversity and potential health benefits of these macroalgae (seaweed) species, suggesting their suitability as functional foods or supplements, offering diverse nutritional and therapeutic benefits.

Changes in the storage quality of fresh-cut vegetables using supercritical carbon dioxide treatment

Supercritical carbon dioxide (SCCD) has been studied for its effectiveness in preserving vegetables, but most research has focused on overall changes in the total phenolic, carotenoid and sugar contents. However, the detailed changes in individual nutrients during storage, as well as their relationship, remain largely unexplored. Herein, in this work, high-performance liquid chromatography (HPLC) was used to analyze the variations in individual carotenoids and sugars in SCCD-treated carrots and pumpkins during 21 days of storage. The results demonstrated that SCCD effectively inhibited microbial growth, and maintained the low levels of polyphenol oxidase (PPO) and peroxidase (POD) activity during storage. SCCD also deferred the degradation of carotenoid profile and phenolic compounds. Additionally, SCCD accelerated the hydrolysis of sucrose content while postponing the reduction of glucose and fructose. In summary, the SCCD technique could delay the quality deterioration of fresh-cut vegetables, preserving them with minimal quality changes.

Exploring Ultrasonic Energy Followed by Natural Fermentation Processing to Enhance Functional Properties and Bioactive Compounds in Millet (Pennisetum glaucum L.) Grains

This study explores the effect of ultrasonic treatment followed by fermentation on the in vitro protein digestibility, protein solubility, functional properties, antioxidant activity, total carotenoid content, and gamma-aminobutyric acid (GABA) levels in millet grains. Ultrasonic treatment was applied at different temperatures (20, 40, and 60 °C). The findings indicated significant improvements in phenolic and flavonoid contents and antioxidant activity in terms of the results of the DPPH, FRAP, and ABTS assays of millet grains after ultrasonic treatment alone or combined with fermentation. Moreover, the carotenoid and GABA contents were found to be significantly higher in the ultrasonic-treated grains. The protein solubility functional properties of the millet grains were also improved after the ultrasonic treatment alone or coupled with the fermentation process. Principal component analysis (PCA) revealed that the combined ultrasonic treatment and fermentation of the millet grains could enhance their antioxidant activity, functional characteristics, and vital compounds. Furthermore, the partial least squares (PLS) validation model emphasised that the ultrasonic treatment of millet at 40 °C, followed by fermentation, is the most optimal treatment among the other treatments. Hence, the conclusions highlight the potential of combined ultrasonic (40 °C) and fermentation treatments to improve grains’ nutritional value and functional properties, making millet more suitable for use in health-promoting food products.

Evaluation of electron beam irradiation on the microbiological, phytochemicals, and aromatic profiles of three paprika (Capsicum annuum L.) varieties

This study provides a comprehensive evaluation of the efficacy of electron beam irradiation (EBI) for microbial decontamination and its effects on the physicochemical properties of three paprika (Capsicum annuum L.) varieties. EBI significantly reduced the total populations of bacteria, yeasts, and molds, rendering them almost undetectable at an irradiation dose of 10 kGy (p < 0.05). The color properties of EBI-treated samples showed no significant changes compared to untreated controls (p > 0.05). The total carotenoid content in S17, H23, and QJ irradiated with 25 kGy decreased by 16.91 %, 22.09 %, and 24.76 %, respectively. There was a 10.82 % increase in DPPH scavenging activity in S17 paprika samples treated with 20 kGy of EBI. Notably, no significant difference in capsaicin content was observed in H23 and QJ varieties, regardless the EBI dose increased (p > 0.05). Additionally, analysis of volatile compounds suggested that the formation of new compounds (n-methyl pyrrole and dihydroactinidiolide) was increased as the radiation doses increased. The overall results suggested that EBI treatment up to 10 kGy demonstrated a high level of effectiveness in microbial inactivation while preserving the essential physicochemical properties of paprika. Industrial relevancePaprika is an indispensable condiment in people's diets and a crucial component of the chili industry. However, it is susceptible to microbial contamination during processing, leading to food safety concerns. Irradiation treatment can inactivate microorganisms and enhance the quality of paprika. This study demonstrates that EBI can effectively achieve microbial decontamination, reduce post-harvest losses, improve the hygienic quality of paprika, and provide a technical reference for the safety of paprika and other spices.

Influence of Electrical Conductivity on Plant Growth, Nutritional Quality, and Phytochemical Properties of Kale (Brassica napus) and Collard (Brassica oleracea) Grown Using Hydroponics

Kale (Brassica napus) and collard (Brassica oleracea) are two leafy greens in the family Brassicaceae. The leaves are rich sources of numerous health-beneficial compounds and are commonly used either fresh or cooked. This study aimed to optimize the nutrient management of kale and collard in hydroponic production for greater yield and crop quality. ‘Red Russian’ kale and ‘Flash F1’ collard were grown for 4 weeks after transplanting in a double polyethylene-plastic-covered greenhouse using a nutrient film technique (NFT) system with 18 channels. Kale and collard were alternately grown in each channel at four different electrical conductivity (EC) levels (1.2, 1.5, 1.8, and 2.1 mS·cm−1). Fresh and dry yields of kale increased linearly with increasing EC levels, while those of collard did not increase when EC was higher than 1.8 mS·cm−1. Kale leaves had significantly higher P, K, Mn, Zn, Cu, and B than the collard at all EC levels. Additionally, mineral nutrients (except N and Zn) in leaf tissue were highest at EC 1.5 and EC 1.8 in both the kale and collard. However, the changing trend of the total N and NO3- of the leaves showed a linear trend; these levels were highest under EC 2.1, followed by EC 1.8 and EC 1.5. EC levels also affected phytochemical accumulation in leaf tissue. In general, the kale leaves had significantly higher total anthocyanin, vitamin C, phenolic compounds, and glucosinolates but lower total chlorophylls and carotenoids than the collard. In addition, although EC levels affected neither the total chlorophyll or carotenoid content in kale nor glucosinolate content in either kale or collard, other important health-beneficial compounds (especially vitamin C, anthocyanin, and phenolic compounds) in kale and collard leaves reduced with the increasing EC levels. In conclusion, the kale leaf had more nutritional and phytochemical compounds than the collard. An EC level of 1.8 mS·cm−1 was the optimum EC level for the collard, while the kale yielded more at 2.1 mS·cm−1. Further investigations are needed to optimize nitrogen nutrition for hydroponically grown kale.

Research on technological process for production of muskmelon juice (Cucumis melo L.)

Abstract The effects of hydrolysis of muskmelon pomace on fruit juice recovery efficiency, transmittance, total phenolic content, total ascorbic acid content, total flavonoid content, and total carotenoid content have been studied. The aim of this study was to evaluate the potential use of pectinase enzyme in the hydrolysis process, specifically looking at the effects of pH, temperature, time, and enzyme concentration on the production of effective muskmelon juice. Additionally, the optimal mixing ratio of ingredients such as melon juice content, Brix level, citric acid, and additives (pectin, sodium carboxymethyl cellulose [CMC], xanthan gum) was investigated to create a high-quality muskmelon juice product. The results showed that using a pectinase enzyme concentration of 0.2%, a pH of 5.0, and a hydrolysis temperature of 45°C for 120 min resulted in a muskmelon juice product with a hydrolyzed juice content of 20%, a Brix level of 12%, and a citric acid addition rate of 0.04%. The addition of xanthan gum at a rate of 0.03% also contributed to the desired flavor and color of the juice. These findings provide valuable insights for the development of effective muskmelon juice processes.

Antioxidant activity of Micractinium sp. (Chlorophyta) extracts against H2O2 induced oxidative stress in human breast adenocarcinoma cells

In response to the growing demand for high-value bioactive compounds, microalgae cultivation has gained a significant acceleration in recent years. Among these compounds, antioxidants have emerged as essential constituents in the food, pharmaceutical, and cosmetics industries. This study focuses on Micractinium sp. ME05, a green microalgal strain previously isolated from hot springs flora in our laboratory. Micractinium sp. cells were extracted using six different solvents, and their antioxidant capacity, as well as total phenolic, flavonoid, and carotenoid contents were evaluated. The methanolic extracts demonstrated the highest antioxidant capacity, measuring 7.72 and 93.80 µmol trolox equivalents g−1 dry weight (DW) according to the DPPH and FRAP assays, respectively. To further characterize the biochemical profile, reverse phase high-performance chromatography (RP-HPLC) was employed to quantify twelve different phenolics, including rutin, gallic acid, benzoic acid, cinnamic acid, and β-carotene, in the microalgal extracts. Notably, the acetone extracts of Micractinium sp. grown mixotrophically contained a high amount of gallic acid (469.21 ± 159.74 µg g−1 DW), while 4-hydroxy benzoic acid (403.93 ± 20.98 µg g−1 DW) was the main phenolic compound in the methanolic extracts under heterotrophic cultivation. Moreover, extracts from Micractinium sp. exhibited remarkable cytoprotective activity by effectively inhibiting hydrogen peroxide-induced oxidative stress and cell death in human breast adenocarcinoma (MCF-7) cells. In conclusion, with its diverse biochemical composition and adaptability to different growth regimens, Micractinium sp. emerges as a robust candidate for mass cultivation in nutraceutical and food applications.

Trade-Off Between Growth Regimes in Chlorella vulgaris: Impact on Carotenoid Production

With the increasing awareness of socio-environmental issues, a global trend has emerged emphasizing the valorization of natural ingredients that promote health and well-being within sustainable production systems, such as microalgae-based carotenoids. Currently, little is understood about the correlation between biomass productivity and carotenoid content, which is a fundamental parameter for facilitating the immediate expansion of microalgae bioprocesses and ensuring the availability and industrial viability of these compounds. In this context, this study aims to investigate the carotenoid profile of Chlorella vulgaris through growth curve experiments conducted under photoautotrophic and heterotrophic regimes. Additionally, a trade-off analysis was performed for the production of carotenoids from microalgae. Carotenoids were quantified using high-performance liquid chromatography coupled with diode array and mass spectrometry detectors (HPLC-PDA-MS/MS). The performance of kinetic phases and energy demands across growth regimes was assessed to provide insights into production trade-offs. The results indicated that a total of 22 different carotenoids were identified in all the extracts. The all-trans-lutein and all-trans-β-carotene were the majority compounds. The total carotenoid content of Chlorella vulgaris revealed significant differences in the kinetic phases of carotenoid production, indicating that carotenoid volumetric production is only viable if the cultures are conducted until the log and stationary phases, based on the function of the biomass volumetric production (weight.volume−1). Therefore, the best trade-off for the process was to provide photoautotrophic growth until the exponential phase (log). Under this condition, the maximum carotenoid and lutein content was 2921.70 µg.L−1, reaching a maximum cell biomass of 1.46 g.L−1. From an environmental/economic point of view, the energy demand was 7.74 kWh.L−1. Finally, the scientific advances achieved in this study provide a holistic view of the influence of the main cultivation methods on the production of microalgae carotenoids, suggesting a viable initial direction for different industrial applications.

Effect of Biomass Drying Protocols on Bioactive Compounds and Antioxidant and Enzymatic Activities of Red Macroalga Kappaphycus alvarezii.

Kappaphycus alvarezii is a red seaweed used globally in various biotechnological processes. To ensure the content and stability of its bioactive compounds postharvest, suitable drying protocols must be adopted to provide high-quality raw materials for industrial use. This study aimed to analyze the influence of freeze-drying and oven-drying on the total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (FRAP and DPPH assays), total carotenoid content (TC), and lipase (LA) and protease activity (PA) of K. alvarezii samples collected over the seasons in sea farms in southern Brazil. The freeze-drying technique was found to be more effective regarding superior contents of TPC (39.23 to 127.74 mg GAE/100 g) and TC (10.27 to 75.33 μg/g), as well as DPPH (6.12 to 8.91 mg/100 g). In turn, oven-drying proved to be the best method regarding the TFC (4.99 to 12.29 mg QE/100 g) and PA (119.50 to 1485.09 U/g), with better performance in the FRAP (0.28 to 0.70 mmol/100 g). In this way, it appears that the drying process of the algal biomass can be selected depending on the required traits of the biomass for the intended industrial application. In terms of cost-effectiveness, drying the biomass using oven-drying can be considered appropriate.

Exogenous 5-aminolevulinic acid promotes carotenoid accumulation in tomato fruits by regulating ethylene biosynthesis and signaling.

5-Aminolevulinic acid (ALA) can not only improve fruit yield and quality, but also increase the lycopene content in tomato fruits. Furthermore, ALA has been shown to promote system-2 ethylene production in tomato fruits. However, the specific interactions between ALA and ethylene during fruit ripening remain unclear. In this study, we treated tomato fruits with ALA, 1-aminocyclopropane-1-carboxylic acid (ACC), aminooxyacetic acid (AOA) + AgNO3, and AOA + AgNO3 + ALA and analyzed ethylene emissions, carotenoid contents, and the relative gene expression levels related to fruit ripening, carotenoid contents, ethylene synthesis, and signal transduction. The ALA treatment significantly enhanced ethylene bursts and carotenoid accumulation, and significantly upregulated the expression of ethylene and carotenoid-related genes, such as SlACS2, SlACS4, SlACO1, SlPSY1, and SlPDS. We also observed that the gene expression levels associated with carotenoid synthesis were downregulated in fruits treated with a combination of ethylene inhibitors (AOA + AgNO3). However, there was a significant upregulation in the gene expression levels associated with carotenoid synthesis and an increase in carotenoid content when fruits were treated with AOA + AgNO3 + ALA. After silencing SlACO1 expression, the total carotenoid content and SlPSY1 expression decreased significantly, while this effect was reversed after exogenous application of ALA. These results indicated that ALA promotes carotenoid accumulation in tomato fruits by promoting ethylene biosynthesis. In conclusion, our results highlighted the role of ALA in promoting carotenoid accumulation and ripening in tomato fruits by regulating ethylene synthesis, thereby providing a novel strategy for improving fruit quality.