Chemical-sensory properties and consumer preference of hibiscus beverages produced by improved industrial processes

Development of a scalable, high-anthocyanin and low-acidity natural red food colorant from Hibiscus sabdariffa L

The hibiscus calyx contains 0.3-2.4% total anthocyanins, and is a promising source for naturally red food colorants. In this study, commercially available hibiscus calyces were subjected to ethanolic-aqueous extraction and chromatographic enrichment with the XAD-7HP resin, to create scalable, high-anthocyanin and low-acidity natural food colorants. Anthocyanins, organic and phenolic acids were monitored after each step using UHPLC-DAD and UHPLC-QQQ/MS. 75.67% total anthocyanins were recovered from calyces after double extractions, and the content increased by 8.50-14.90 times after the column enrichment, reaching 14.51-31.90% (by dry weight) in the final product. Chromatographic fractionation was also shown to effectively increase the total phenolic acids by 11.01-16.22 times, and remove an average of 98.58% of the total organic acids. High intensity redness at pH 2.5-3.5 indicated that the final product may be a promising, versatile natural food and beverage colorant in low pH products.

Determination of anthocyanins, organic acids, and phenolic acids in hibiscus market products using LC/UV/MS

Hibiscus sabdariffa has gained increasing attention from consumers as a natural, healthy food ingredient, leading to a myriad of available products, yet there is a lack of understanding of the quality and chemical diversity among commercially available hibiscus products. Here, we conducted a survey on the chemistry of 29 hibiscus products (calyces, beverages, and extracts). UHPLC-DAD and UHPLC-QQQ/MS methods with high sensitivity and selectivity were developed to evaluate the chemical profiles pertaining to the sensory attributes (color and taste). Two major anthocyanins (delphinidin-3-sambubioside and cyanindin-3-sambubioside), eight organic acids, and 23 phenolic acids were identified and quantified in hibiscus market products. The results showed that hibiscus samples contained < 0.001-2.372% of total anthocyanins, 0.073-78.002% of total organic acids, and 0.001-1.041% of total phenolic acids, and demonstrated significant variations in market products. This is the first time that an in-depth organic acid profiling was conducted on hibiscus products using UHPLC-QQQ/MS. This method can also be extended to chemical profiling, sensory analysis, quality control, authentication, and standardization of other natural products.

Advanced interactional characterization of the inhibitory effect of anthocyanin extract from Hibiscus sabdariffa L. on apple polyphenol oxidase

In this study, a comprehensive approach to advance the inhibitory effect of Hibiscus sabdariffa extract on apple polyphenol oxidase (PPO) was performed. PPO was extracted, purified, and characterized for optimal activity, whereas response surface methodology generated a quadratic polynomial model to fit the experimental results for hibiscus extraction. The optimum conditions allowed to predict a maximum recovery of anthocyanins (256.11 mg delphinidin-3-O-glucoside/g), with a validated value of 272.87 mg delphinidin-3-O-glucoside/g dry weight (DW). The chromatographic methods highlighted the presence of gallic acid (36,812.90 µg/g DW extract), myricetin (141,933.84 µg/g DW extract), caffeic acid (101,394.07 µg/g DW extract), sinapic acid (1157.46 µg/g DW extract), kaempferol (2136.76 µg/g DW extract), and delphinidin 3-O-β-d-glucoside (226,367.08 µg/g DW extract). The inactivation of PPO followed a first-order kinetic model. A temperature-mediated flexible fit between PPO and anthocyanins was suggested, whereas the molecular docking tests indicated that PPO is a good receptor for cafestol, gallic acid, and catechin, involving hydrophobic and hydrogen bond interactions. PRACTICAL APPLICATION: It is well known that enzymatic browning is one of the most important challenges in the industrial minimal processing of selected fruit and vegetable products. Novel inhibitors for polyphenol oxidase are proposed in this study by using an anthocyanin-enriched extract from Hibiscus sabdariffa L. Based on our results, combining the chemical effect of phytochemicals from hibiscus extract with different functional groups with minimal heating could be an interesting approach for the development of a new strategy to inhibit apple polyphenol oxidase.

Production of low-tannin Hibiscus sabdariffa tea through D-optimal design optimization of the preparation conditions and the catalytic action of new tannase

Many tannase-based industrial applications are currently being developed to successfully break down tannins in teas and juices. However, so far, no study has demonstrated the potential application of tannase to reduce tannin levels in Hibiscus sabdariffa tea. The D-optimal design was utilized to predict the optimal conditions for maximizing anthocyanins and decreasing tannin content in Hibiscus tea. Then, the effects of Penicillium commune tannase were evaluated by examining the physicochemical parameters and α-amylase inhibitory action of untreated and treated Hibiscus tea, as well as quantifying catechin content changes using HPLC. Following treatment with tannase, the esterified catechins decreased by 8.91%, while the non-esterified catechins increased by 19.76%. Additionally, tannase significantly raised the total phenolic compounds by 8.6%. In contrast, the α-amylase inhibiting activity of Hibiscus tea decreased by ≈28%. As a novel member of the tea family, tannase offers an excellent means of conditionally producing low-astringency Hibiscus tea.

Evaluation of the intensity of cigarette odors based on the perception of consumers

INTRODUCTION

We evaluated the tobacco odor intensity of cigarettes based on a large consumer panel and explored the differences of odor intensity perception based on sex, age and smoking habits.

METHODS

The perceived intensity of tobacco odor of cigarettes was evaluated using a consumer group method. A consumer panel of 240 volunteers (80 smokers, 80 ex-smokers and 80 non-smokers) was asked to smell eleven unlit cigarettes and then report their tobacco odor intensity in a specific questionnaire.

RESULTS

All volunteers clearly determined the presence of tobacco odor in all cigarettes. There is a general decrease of the perceived odor intensity with age, for both males and females. Moreover, tobacco odor perceived intensity, among all volunteer groups (smokers, non-smokers, ex-smokers), was higher for females than for males. Non-smokers declared the highest perceived tobacco odor intensities, followed by ex-smokers and smokers, who recorded the lowest perceived odor intensity. Perceived odor intensity decreased with age, with a higher rate for females compared to males, but independently of the smoking habits.

CONCLUSIONS

Regular and untrained consumers confirmed that a tobacco odor of different intensity can be perceived during the smelling of unlit cigarettes. This perceived intensity depends on sex, age and smoking habits.

Application of mixture design methodology for development of high antioxidant fruity functional beverage

Three red color fruit juice (pomegranate (PJ), barberry (BJ), and grape juice (GJ)) and three plant extracts (cardamom essential oil (CE), ginger extract (GE), and hibiscus solution (HS)) were used for the development of different functional beverages. Organoleptic analysis was done to detect the most acceptable fruit juice blend. The physicochemical properties of the samples including total phenols, 1,1-diphenyl-2-picrylhydrazyl (DPPH) inhibition percent, anthocyanin, flavonoid, and vitamin C content of optimum fruit juice blend (60% PJ/20% BJ/20% GJ) were 121.57 µg gallic acid equivalent (GAE)/ml, 80.28%, 4.03 mg/L, 64.87 mg/100 ml, and 51.10 mg/100 ml, respectively. To determine the optimum level of extracts and essential oil (GE, CE, and HS) in fruit juice blends, the mixture design method was used and 14 runs (formulations) were obtained. In all formulations, samples containing HS had the highest content of antioxidant and active components and the statistical analysis indicated that the sample containing 0.5 CE/0.5 GE/1 HS (ml/100 ml) had the optimum content of antioxidant components. Thus, the results of this study introduce a functional drink possessing high polyphenols, antioxidants, anthocyanin, and vitamin C content.

An interdisciplinary and participatory methodology to improve user acceptability of root, tuber and banana varieties

Breeding programmes for root, tuber and banana (RTB) crops have traditionally considered consumer demand for quality characteristics as low priority against other considerations such as yield and disease resistance. This has contributed to low levels of adoption of new varieties and its potential benefits. To address these challenges, an interdisciplinary five‐step methodology was developed to identify demand for quality characteristics among diverse user groups along the food chain. The methodology includes an evidence review, consultations with key informants and rural communities, processing diagnosis with experienced processors and consumer testing in urban and rural areas. Quality characteristics are then prioritised into a Food Product Profile by user group to inform further work of biochemists and breeders in developing improved selection tools. This initiative presents a new basis to understand consumer preferences for RTB crops. The methodology is currently being applied in projects in sub‐Saharan Africa and is applicable globally.

Concentration of roselle (Hibiscus sabdariffa L) and sucrose in beverages: Effects on physicochemical characteristics and acceptance

The calyces of roselle (Hibiscus sabdariffa L.) are used to make a refreshing drink with high content of anthocyanins and other phenolic compounds, although the process for obtaining the beverage is not standardized. In this research it was determined physicochemical characteristics, total soluble polyphenols content, antioxidant activity and acceptance for beverages prepared by decoction at four concentrations of calyces in water (1.0, 2.5, 5.0 and 10.0%) and two concentrations of sucrose (11 and 16%). Color parameters in beverages permitted to describe them as red, which turned darker as the content of hibiscus increased. Total soluble polyphenols content and antioxidant activity were directly correlated with content of calyces in beverages and inversely correlated with pH, which means that beverages with higher content of calyces could be perceived as more acidic and more intense in characteristics associated with hibiscus presence, such as acid, astringent and the presence of intense dark red color, although the higher concentration of sucrose might have contributed to mask slightly the sourness and astringency. Acceptance for hibiscus beverages allowed to observe two segments of consumers, high-intensity and low-intensity likers but both confluence in overall liking values for beverages prepared with 2.5% calyces and 16% sucrose.

Anthocyanin-rich extracts from purple and red potatoes as natural colourants: Bioactive properties, application in a soft drink formulation and sensory analysis

Aqueous extracts from seven coloured potato varieties (three red-fleshed, three-purple fleshed, and one marble-fleshed) were studied for their anthocyanin content, in vitro biological activities, colouring properties and their potential application in the food industry. Acylated glycosides or pelargonidin and petunidin aglycones were identified as the main anthocyanin forms in the red and purple varieties, respectively. The total anthocyanin content among varieties ranged from 478.3 to 886.2 mg/100 g extract. All the extracts presented in vitro antioxidant, antibacterial and antifungal activities, whereas no toxic effects were detected. Finally, two selected extracts were tested as colourants in a soft drink formulation and presented suitable sensory profiles as well as high colour stability during a 30-day shelf-life when compared with the commercial colourant E163. Therefore, the tested extracts could be used as natural food colourants and considered for substituting the existing synthetic colouring agents.

Potassium bromate cytotoxicity in the Wister rat model of chronic gastric ulcers: Possible reversal by protocatechuic acid

The interaction between ingested xenobiotics and the gastrointestinal epithelium influences the possibility of gut epithelial cytotoxicity and systemic toxicity. Potassium bromate (KBrO₃ ) has been shown to perturb the central nervous system and it may be carcinogenic, albeit it is used as a food additive. This highlights the need to understand KBrO₃ 's effect on the stomach epithelium. Here, we report the cytotoxic potential of KBrO₃ in an ulcerated stomach, as well as possible cytoprotection by the polyphenol - protocatechuic acid. Potassium bromate (12.5 mg/kg) and protocatechuic acid (120 mg/kg) were administered orally while omeprazole (20 mg/kg) was used as standard. Potassium bromate exacerbated gastric ulcers, increased malonaldehyde levels, catalase, and sodium pump activities, but reduced nitric oxide levels. Potassium bromate further increased mast cell count in the muscularis mucosa, while inducing chronic inflammation and moderate angiogenesis in the gastric mucosa. Our results delineate KBrO₃ -induced gastric epithelial cytotoxicity that is ameliorated by protocatechuic acid. PRACTICAL APPLICATIONS: Potassium bromate is a known food additive in the baking, brewing, and cheese-making process. Conversely, protocatechuic acid (3,4-dihydroxybenzoic acid) is the polyphenolic content of plants like Hibiscus sabdariffa L that are commonly consumed as herbal drink, food, spices, and used in folk medicine. This study reports the cytoprotective effect of protocatechuic acid against gastric mucosa ulceration that has been aggravated by potassium bromate.

A novel sustainable approach for the extraction of value-added compounds from Hibiscus sabdariffa L. calyces by natural deep eutectic solvents

Hibiscus sabdariffa L. is widely acknowledged as an important source of value-added compounds as natural pigments and bioactive compounds whose isolation is of great interest in food industry. Due to the incessant demand of green extraction procedures, NADESs have emerged in the last years as new green solvents alternative to the conventional organic ones. The feasibility of NADESs for the extraction of value-added compounds of H. sabdariffa has been assessed in this work for the first time. An extraction technique based on microwave assisted extraction (MAE) and the use of NADESs was proposed testing different deep eutectic solvents based on choline chloride (ChCl). Among them, oxalic acid based NADES exhibited a great selectivity for anthocyanins in particular as well as higher extraction yields of bioactive compounds was also observed, even greater than those observed by methanol. The effect of extraction variables such as liquid-solid ratio, temperature and water percentage were studied by Box-Behnken design and a response surface methodology. The statistical program pointed out the liquid-solid ratio of 1:30 mL mg^-1, temperature of 75 °C and a water percentage of 55% as the conditions to maximize extraction within the experimental domain. Hence, NADES composed by oxalic acid and choline chloride resulted to be an effective green alternative tailor-made solvent to carry out selective extractions of value-added compounds from H. sabdariffa.

Effect of extract or infusion of leaves of the Hibiscus sabdariffa L. in the production and storage of the beverage blends with cupuassu: physico-chemical and sensory acceptance

This study aimed to produce beverages using extract or infusion of Hibiscus sabdariffa leaves with cupuassu pulp. The blended drinks with cold or hot extraction were formulated using the response surface methodology. Moreover, the physico-chemical and sensory stability of these beverages was performed for 180 days. The conditions production for beverage leaf extract were: 28% leaf extract, 72% cupuassu pulp, and 14°Brix. For beverage leaf infusion, were 37% leaf extract, 63% cupuassu pulp, and 13°Brix. Comparing the two beverages, the polyphenolic compounds and the antioxidant activity (ABTS and DPPH) were higher in the blends produced with leaf extract. Thus, the cold extract provided better extraction of these components in the leaves. During storage, pH, reducing and total sugars and soluble solids of blends increased linearly (p < 0.05). Nevertheless, vitamin C, polyphenolic compounds, and the antioxidant activity reduced linearly (p < 0.05). The sensory acceptance of blends containing leaf extract, in the hedonic scale, all sensory attributes were positively scored up to 135 days. At 180 days, the acceptance reduced for rejection. The blended beverage containing leaf infusion had all sensory attributes positively scored up to 90 days, with a rating between 6.27 and 7.42. At 135 and 180 days, the values were in the indifference region of the hedonic scale or acceptance region. Therefore, the blend with leaf infusion maintained better acceptance during storage when compared to leaf extract beverage. Thus, the blended beverages had good nutritional value and sensory acceptance and were acceptable for up to 135 days.

Formulation and characterization of an optimized functional beverage from hibiscus (Hibiscus sabdariffaL.) and green tea (Camellia sinensisL.)

Hibiscus sabdariffa and Camellia sinensis are traditionally consumed as beverages and are good sources of health-promoting phenolic compounds. The objective of this work was to use response surface methodology to develop an optimized functional beverage with high total phenolic content, antioxidant capacity, and acceptable for potential consumers. Optimum infusion conditions were 4.9 g of hibiscus calyces or C. sinensis leaves/100 ml of water at 26 ℃ for 291 min. These conditions yielded a total phenolic content of 14.80 ± 1.4 and 33.02 ± 0.34 mg gallic acid equivalents/100 ml for hibiscus and green tea, respectively. The optimized beverages were combined in a 7:3 (hibiscus:green tea, v/v) ratio; a consumer preference test showed that this combination had an acceptable taste according to untrained panelists. A chromatographic analysis showed that this formulation contained flavonoids, phenolic acids, and anthocyanins as its main components. Our data suggested that hibiscus and green tea phenolic compounds were efficiently extracted using near-ambient temperature water for prolonged times, contrary to routine methods (high temperature, short time). Our method also preserved antioxidant capacity, possibly by avoiding chemical changes/degradation due to high temperatures. This process can be used to produce organoleptically acceptable functional beverages that deliver a varied phenolic compound profile to the consumer.

Chemistry, pharmacology and new trends in traditional functional and medicinal beverages

Functional and medicinal beverages consumption plays an important role in human health, considering that metabolites, with a wide range of pharmacological effects, are inserted in the human diet. Nowadays, the most consumed beverages are obtained from Camellia sinensis leaves and coffee grain processing, and contain different classes of polyphenols and phenolic acids in their phytochemical composition. Besides C. sinensis and coffee, numerous plants have been receiving attention due to their phytochemical composition and pharmacological effects, such as yerba mate, hibiscus, chamomile, lemongrass, fennel and mentha. Furthermore, atomized or lyophilized medicinal plant extracts can be employed in many beverage formulations and the consumption of these products is an excellent delivery means for nutrients and bioactive compounds, such as: minerals, vitamins, terpenes, antioxidants, saponins, alkaloids and polysaccharides. Innovation in food processing in order to insert functional and medicinal beverages in the human diet poses a challenge for the coming years. The technological development of new processing forms and use of plants with bioactive metabolites could be an important tool in relation to this proposal. In this context, this review has aimed to summarize and analyze pharmacological, phytochemistry and technological aspects of species with classical ethnobotanical and traditional use.