A method for red-violet pigments extraction from fruits of Malabar spinach (Basella rubra) with enhanced antioxidant potential under fermentation

The indigenous microbial diversity involved in the spontaneous fermentation of red dragon fruit (Hylocereus polyrhizus) identified by means of molecular tools

Red dragon fruit (RDF) is well-known for its high nutritional content, especially the red pigment betacyanins that possess high antioxidant activity. Natural fermentation is an ancient yet outstanding technique that relies on the autochthonous microbiota from fruits and vegetables surfaces to preserve and improve the nutritional values and quality of the food product. The present study was to evaluate and identify the indigenous microbial community (bacteria and fungi) that are involved in the natural fermentation of RDF. Results revealed a total of twenty bacterial pure cultures and nine fungal pure cultures were successfully isolated from fermented red dragon fruit drink (FRDFD). For the first time, the PCR amplification of 16S rRNA and ITS regions and sequence analysis suggested nine genera of bacteria and three genera of fungi (Aureobasidium pullulans, Clavispora opuntiae, and Talaromyces aurantiacus) present in the FRDFD. Four dominant (≥10 % isolates) bacteria species identified from FRDFD were Klebsiella pneumonia, Brevibacillus parabrevis, Bacillus tequilensis and Bacillus subtilis. The carbohydrate fermentation test showed that all the indigenous microbes identified were able to serve as useful starter culture by fermenting sucrose and glucose, thereby producing acid to lower the pH of FRDFD to around pH 4 for better betacyanins stability. The present study provides a more comprehensive understanding of the indigenous microbial community that serves as the starter culture in the fermentation of RDF. Besides, this study provides a useful guide for future research to be conducted on studying the rare bacterial strains (such as B. tequilensis) identified from the FRDFD for their potential bioactivities and applications in medical treatment and functional foods industries.

Structural Studies on Diverse Betacyanin Classes in Matured Pigment-Rich Fruits of Basella alba L. and Basella alba L. var. ‘Rubra’ (Malabar Spinach)

Identification of betacyanins in Basella alba L. and Basella alba L. var. ‘Rubra’ fruits was performed by low- and high-resolution mass spectrometry (LRMS and HRMS) as well as ¹H, ¹³C and two-dimensional NMR which revealed hitherto completely not known betacyanin classes in the plant kingdom. Especially, the presence of unique nitrogenous acyl moieties in the structures of the pigments was ascertained by the HRMS Orbitrap detection. Except for detected polar betacyanin glycosylated derivatives, presence of a series of previously not reported pigments such as malonylated betanidin 6-O-β-glusosides with their acyl migration isomers along with the evidence of the 3′′-hydroxy-butyrylated betacyanins is reported. The first complete NMR data were obtained for novel and principal acylated gomphrenins with hydroxycinnamic acids: 6′-O-E-caffeoyl-gomphrenin (malabarin), 6′-O-E-sinapoyl-gomphrenin (gandolin), 6′-O-E-4-coumaroyl-gomphrenin (globosin) and 6′-O-E-feruloyl-gomphrenin (basellin).

Fermentation of red pitahaya extracts using Lactobacillus spp. and Saccharomyces cerevisiae for reduction of sugar content and concentration of betacyanin content

A study was conducted to concentrate the betacyanin in red pitahaya extracts by removing the coexisting sugars by fermentation. Four lactic acid bacteria (Lactobacillus acidophilus, L. casei, L. rhamnosus and L. plantarum) and a yeast species (Saccharomyces cerevisiae) were screened to determine their efficiency to reduce sugar content in red pitahaya extracts for concentration of their betacyanin content. A reduction of sugar content (19.8-56.4%) and increase in the yield of betacyanins were observed in all extracts as compared to the control, which was not innoculated with any microorganisms after 1 day of fermentation. The lowest total sugar content (26.40 g/L) was observed in extracts fermented by S. cerevisiae. Extracts fermented by S. cerevisiae also showed greater numbers of microbial cells (10.75 log CFU/mL) and a lower pH value (3.54) compared to those (6.89-8.48 log CFU/mL and pH 4.64-5.42) of the Lactobacillus spp. after 1 day of fermentation. An optimization step using response surface methodology (RSM) was then conducted using S. cerevisiae. Temperature, time and agitation speed were found to have a significant effect on the total sugar content and BC of concentrated betacyanins from red pitahaya, while the yield of betacyanins was significantly influenced by temperature and agitation speed.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05116-2.

Study on bioaccessibility of betacyanins from red dragon fruit (Hylocereus polyrhizus)

Betacyanins are bioactive dietary phytochemicals which can be found in red dragon fruit (RDF). Therefore, the bioaccessibility of betacyanins that present in fermented red dragon fruit drink (RDFD) and pressed red dragon fruit juice (RDFJ) was accessed in simulated gastric and intestinal digestion. Results disclosed that betacyanins from RDFD and RDFJ suffered minor loss (< 25%) at gastric-like environment but greater loss was observed during the intestinal phase digestion. After subjected to intestinal digestion, RDFD retained 46.42% of betanin while RDFJ retained 43.76%, with betanin concentration of 17.12 mM and 12.37 mM, respectively. Findings also revealed that RDFD exhibited higher antioxidant capacity compared to RDFJ after subjected to intestinal digestion, with values of 0.88 mM Trolox equivalent antioxidant capacity (TEAC) and 0.85 mM TEAC, respectively. The data suggests that betacyanins that present in RDF are bioaccessible while fermentation able to enhance the bioavailability with more betacyanins retained after intestinal digestion.

Identification and characterization of bioactive phenolic constituents, anti-proliferative, and anti-angiogenic activity of stem extracts of Basella alba and rubra

Basella is an important green leafy vegetable species of Chenopodiaceae family and is known for its medicinal properties. Hydroxy-benzoic acids, hydroxy-cinnamic acids and flavones groups were identified and characterized from the aqueous stem extracts of B. alba and B. rubra species. Higher values of phenolics as well as antioxidant activity were noted from B. alba species extracts. The evaluation of the cytoxicity of these extracts on A431 (epidermoid carcinoma), Hep G2 (hepatocellular carcinoma) and MG 63 (osteosarcoma) cells indicated anti-proliferative activity against all the cell lines. B. alba extract showed higher anti-proliferative activity (37.95-84.86%). Chick embryo chorioallantoic membrane (CAM) assay revealed inhibition of neo-vessels formation. Significant suppression was found with extracts of B. alba at 7 mg/ml compared to that of B. rubra. This is the first study to report the anti-angiogenic activity of Basella species. These studies indicate that Basella sps can be used as a source of natural antioxidants and can be of high significance in pharmaceutical and nutraceutical industries.

Thermal Degradation of Major Gomphrenin Pigments in the Fruit Juice of Basella alba L. (Malabar Spinach)

Generation of decarboxylated and dehydrogenated gomphrenins during heating of Basella alba L. fruit juice containing high levels of betacyanin pigments was monitored by LC-DAD-ESI-MS/MS. The presence of principal decarboxylation products, 2-, 17-, and 2,17-decarboxy-gomphrenins, their diastereomers, as well as minor levels of their dehydrogenated derivatives are reported. In addition, determination of molecular masses of decarboxylated gomphrenins by high-resolution mass spectrometry (LCMS-IT-TOF) was performed. Enzymatic deglucosylation of decarboxylated and dehydrogenated gomphrenins resulted in the generation of betanidin diagnostic derivatives for further identification processes. In addition, experiments were conducted to prove that the position of glucosylation of the chromophoric part of betacyanins (betanidin part) has decisive influence on different chromatographic properties of their decarboxylated derivatives.

Effect of fermentation and sterilization on anthocyanins in blueberry

BACKGROUND

Blueberry products have various health benefits due to their high content of dietary anthocyanins. The aim of this study was to investigate the impact of fermentation and sterilization on total anthocyanin content, composition and some quality attributes of blueberry puree. The blueberry puree used here was fermented for 40 h at 37 °C by Lactobacillus after sterilization. The method of ultra-performance liquid chromatography-mass spectrometry was optimized for the rapid analysis of anthocyanins. Quality attributes including pH, color, total soluble solids and viscosity were measured.

RESULTS

A total of 21 anthocyanins and five anthocyanidins were quantified by ultra-performance liquid chromatography. Fermented blueberry had reduced total anthocyanin content (29%) and levels of individual anthocyanins compared with fresh blueberry. Total anthocyanin content was decreased 46% by sterilization, and different degradation behavior of individual anthocyanin was appeared between fermented and sterilized-fermented blueberry puree. Fermentation and sterilization decreased the total soluble solids and pH and changed color parameters, while minimally influencing viscosity.

CONCLUSIONS

The loss of total anthocyanin content by fermentation was related to the unstable structure of blueberry anthocyanins. Anthocyanins are sensitive to temperature (>80 °C), and degradation of anthocyanins by sterilization in blueberry should be considered in the fermentation procedure. © 2016 Society of Chemical Industry.

Phytoconstituents and stability of betalains in fruit extracts of Malabar spinach (Basella rubra L.)

This study aimed to assess the nutrient composition, minerals, and stability of betalains pigment from fruit extracts of Basella rubra. The proximate composition included total carbohydrates (1.64 g), protein (51 mg), total lipid (1.38%), moisture (81.76%), niacin (0.5 mg), ascorbic acid (89.33 mg), and total tocopherols (1.27 mg) in 100 g fresh deseeded fruit. Total dietary fibre of 32.52 g and soluble dietary fibre of 12.34 g in 100 g dry deseeded fruits. Fatty acid composition of dry deseeded fruits comprised 57.52% SFA, 20.62% MUFA and 22.28% PUFA. Pigment (betalain) rich fruit extracts showed excellent stability over 20 days of storage under varied pH, temperature, light, acids, salts and sugars. B. rubra fruit was observed as a potential source of nutrients and betalains as a functional food.

Impact of extraction and processing conditions on betalains and comparison of properties with anthocyanins - A current review

The search for natural pigments has been driven by growing evidence indicating that synthetic colorants can cause deleterious health effects. Betalains, in addition to anthocyanins, have been proposed as an alternative to address this need. However, the incorporation of natural pigments poses some challenges to the food industry, such as reduced stability in comparison to their synthetic counterparts. Moreover, betalains are not well studied in comparison to anthocyanins and information about the effects of processing on their physicochemical properties and stability is scattered. Thus, this review will provide an overview of the recent research on the extraction and processing of betalains from natural sources, and comparison of their colorant and physicochemical properties with anthocyanins.

Plant Betalains: Safety, Antioxidant Activity, Clinical Efficacy, and Bioavailability

Betalains are accepted food additives derived from vacuoles of plants belonging to about 17 families in the order Caryophyllales. These pigments are composed of a nitrogenous core structure, betalamic acid [4-(2-oxoethylidene)-1,2,3,4-tetrahydropyridine-2,6-dicarboxylic acid]. Betalamic acid condenses with imino compounds (cyclo-DOPA and/or its glucosyl derivatives) or amines and/or their derivatives to form violet betacyanins (for example, betanin) and yellow betaxanthins (for example, indicaxanthin), respectively. Till date, structures of 75 betalains have been elucidated from plants under the order Caryophyllales. The extracted betalains are safe to consume and they act as micronutrients in the body. In vitro studies to highlight radical-scavenging activity, cell culture studies to assess cytotoxicity and absorption of betalains, and proven clinical efficacies are compiled in this review. The literature on biological activity has not been analyzed for a synthesis of safety, clinical efficacy, and bioavailability to arrive at the concentrations required for the purported health benefits. Most betalains are under-utilized in pharmaceutical and cosmetic preparations due to poor stability and lack of scientific reports highlighting their superior tinctorial strength including flourescence, water solubility, and functional value alongside their bioavailability. This is the first comprehensive review on the dietary safety, biological activity and bioavailability of betalains. Based on this review, for future debate and input from health professionals, a human daily intake of betanin and indicaxanthin can be proposed at 100 and 50 mg, respectively.

Characterization of major betalain pigments -gomphrenin, betanin and isobetanin from Basella rubra L. fruit and evaluation of efficacy as a natural colourant in product (ice cream) development

Basella rubra L. (Basellaceae) commonly known as Malabar spinach is a leafy vegetable which accumulates pigments in its fruits. To find out the feasibility of utilizing pigment rich extracts of its fruit as natural food colourant, fruits at different stages were analysed for pigment profiling, carbohydrate content, physical dimensions and weight. Total betalains content increased rapidly from early (green) through intermediate (half-done red-violet) to matured stage (red-violet). Maximum pigment content was observed in ripened fruits (143.76 mg/100 g fresh weight). The major betalain pigment characterized was gomphrenin I in ripened fruits (26.06 mg), followed by intermediate fruits (2.15 mg) and least in early fruits (0.23 mg) in 100 g of fresh deseeded fruits. Total carbohydrates content and the chroma values (redness) were also increased during ontogeny of B. rubra fruits. The textural characters of developing fruits showed the smoothness of green fruits with lower rupture force (0.16 N/s) than ripe ones (0.38 N/s). The pigment-rich fruit extract was used as natural colourant in ice-cream, to evaluate its effect on physicochemical properties and acceptability of the product. After six months of storage at -20 °C, 86.63 % colour was retained in ice-cream. The ice-cream had good overall sensorial quality and was liked by consumers indicating that addition of B. rubra fruit extract did not alter the sensory quality of the product. The colour values also indicate that there was no significant decrease of this pigment-rich extracts of fruits for its incorporation in food products.