Hibiscus Extract Research Articles

Starch-Hibiscus-Cellulose Nanofibrils Composite Films as a Model Antimicrobial Food Packaging Material

ABSTRACT The large amounts of coffee husks (CHs) waste matter generated from coffee farms and factories has been considered as a new non-wood source of cellulose. The aim of this work was to fabricate an edible food packaging material from starch incorporating TEMPO-oxidized cellulose nano-fibrils (TOCNFs) and hibiscus extracts to boost its mechanical and antibacterial properties respectively. In this study, three schemes were employed to fabricate this enhanced novel nanocomposite film of starch, hibiscus and TOCNF Firstly, glycerol was used as the plasticizer on the formation of the starch film to give mobility to the α-D-glucose structural chains making the composite film more flexible. Secondly, TEMPO-oxidized cellulose nano-fibers derived from coffee husks were thrown into the mix to enhance the mechanical properties of the starch matrix and to control water vapor permeability and solubility. Lastly, the antimicrobial activity and UV resistance of the films were enhanced through incorporation of hibiscus crude extracts which were infused into the nanocomposite films.

Flower extract-mediated green synthesis of bimetallic Cu[sbnd]Zn oxide nanoparticles and its antimicrobial efficacy in hydrocolloid films

Fruit packaging materials is highly essential in order to maintain freshness and safety from foodborne bacterial infections. Natural hydrocolloids are commonly used as fruit packaging materials to ensure safety and to reduce environmental pollution. However, their poor antibacterial efficacy is significant limitation in fruit packaging application. In the present work, bimetallic (Cu/Zn) nanoparticles (BM-Cu/Zn-NPs) were prepared using aqueous extract of Hibiscus rosa sinensis flowers along with thermal treatment. The surface morphological and chemical properties of the synthesized BM-Cu/Zn-NPs were examined by use of various specific characterization techniques. Furthermore, synthesized BM-Cu/Zn-NPs were incorporated into the hydrocolloids (chitosan (1.5 wt%) and pectin (0.5 wt%)) for the development of nanocomposites hybrid films with antimicrobial activity. The antimicrobial efficacy of the developed hydrocolloid films was evaluated via disc diffusion approach. The results of present study indicated that the BM-Cu/Zn-NPs containing hydrocolloid film could be a promising packaging material for fruit safety.

Formulation of Hair Tonic from Ethanol Extract of Sea Hibiscus (Hibiscus tileaceus L.) Leaves in Promoting Hair Growth on Guinea Pig (Cavia porcellus)

Hair loss is an unavoidable process, as the age increase, the rate of hair growth also slows down. Hair loss is caused by many factors and occur in different areas of body. Since hair become one of the major aspect for women beauty, hair loss will become a serious problem if it is not solved. Many plants or their extracts have been used to reduce hair loss. The leaves of sea hibiscus (Hibiscus tiliaceus L.) have been known empirically to promote hair growth and prevent hair loss. The leaves contain saponin, flavonoid, and also polyphenol compounds. The purpose of this study was to formulate sea hibiscus leaf extract into hair tonic preparations and evaluate the activity in triggering hair growth. In this research, tested animals were divided into 5 groups: F0 (blank) as a negative control, F1 (20%), FII (25%), FIII (30%) extract of sea hibiscus leaves and minoxidil as positive control. All preparations made were kept in room temperature for 12 weeks and the pH value test was carried out in first, fourth, eighth and twelfth week. The hair growth activity was done by applying hair tonic to the guinea pig and hair was randomly plucked from test area measuring hair length using calliper on the 7th, 14th, 21st days. On the 21st day, hair tonic of 30% sea hibiscus leaf extract showed a great activity on the growth of hair length with an average of 17.2633 mm and weighed an average of 0.145g, with a significant difference compared to another formula (p < 0.05).
 Keywords: Hair tonic, Hibiscus tiliaceus, Sea Hibiscus Leaves

Microencapsulation of hibiscus bioactives and its application in yogurt

The aim of this study was to evaluate the application of microparticles of anthocyanins from Hibiscus sabdariffa L. extract, obtained by ionic gelation, to commercial natural yogurt. Two ionic gelation techniques were used as follows: atomization (Spray Dryer B-290) and dripping (Encapsulator B-390). Microparticles produced were evaluated for size, morphology, color, and encapsulation efficiency (total phenolic compounds, anthocyanins, and antioxidant capacity). Hibiscus extract (1.5%–4.5%) and 20% of hibiscus microparticles, obtained by atomization or dripping, were applied to whole sweetened natural yogurt and fat-free natural yogurt. Samples were evaluated for sensory acceptance and color changes under refrigerated conditions after the application of different levels of hibiscus extract (1.5%–4.5%). The atomization technique generated smaller particles with a greater encapsulation efficiency of bioactive compounds. Application of free hibiscus extract (4.5%) and hibiscus microparticles (20%) in yogurt matrix proved to be technically feasible, providing color and functional appeal to the product, with good sensory preference. Novelty Impact Statement The double emulsion followed by ionic gelation has allowed good retention of hibiscus anthocyanins. The atomization technique generated smaller particles with a greater encapsulation efficiency of bioactive compounds. Hibiscus extract combined with microencapsulated hibiscus promoted color and functional appeal to yogurt, with good sensory preference.

A Comparative Study of the Antihypertensive and Cardioprotective Potentials of Hot and Cold Aqueous Extracts of Hibiscus sabdariffa L. in Relation to Their Metabolic Profiles

Ethnopharmacological relevance: Since ancient times, Hibiscus sabdariffa L. calyces have been used as a folk remedy for the treatment of hypertension. However, it is questionable as to whether there is a difference in the antihypertensive activity of the hot or cold aqueous extracts. Aim of the study: We designed this study to specify the best method for water extraction of the antihypertensive metabolites of H. sabdariffa and to confirm their in vivo antihypertensive capabilities. Materials and methods: The powdered dried calyces of H. sabdariffa were independently extracted with cold and hot water. A comparative study was performed between the cold and hot aqueous extracts of H. sabdariffa based on evaluation of the in vitro renin and angiotensin-converting enzyme (ACE) inhibition activities. Additionally, both extracts were subjected to an in vivo study for the evaluation of their antihypertensive activities in L-Nw-Nitro arginine methyl ester (L-NAME)–induced hypertensive rats. Further, a metabolomics study was also performed for both extracts to identify their chemical constituents. Results: The cold and hot extracts significantly reduced the angiotensin II, ACE, and aldosterone levels in the plasma. Furthermore, in the myocardium and aorta, decreased iNOS (inducible nitric oxide synthase) levels and elevated eNOS (endothelial nitric oxide synthase), as well as the rise in plasma NO levels, were reported with both extracts, but better results were displayed with the hot extract, leading to a potential antihypertensive effect. Additionally, the cold and hot Hibiscus extracts induced a cardioprotective effect through reducing necrosis, inflammation, and vacuolization that results from the induction of hypertension, an effect that was more prominent with the hot extract. Moreover, a comprehensive metabolomics approach using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC–MS/MS) was able to trace the metabolites in each extraction. Conclusion: The extracts showed different anthocyanin and phenolic compounds, but the hot extract showed higher contents of specific phenolics to which the superior antihypertensive and cardioprotective activities could be related.

Formulation of gold nanoparticles with hibiscus and curcumin extracts induced anti-cancer activity

Gold nanoparticles (AuNPs) have shown a potential for biological applications due to their biocompatibility and high efficiency in drug delivery. Most of the times, the chemical routs are being used to synthesize the AuNPs products. In this paper, eco-friendly non-chemical rout was used to prepare AuNPs by utilizing hibiscus and curcumin extracts as reducing and stabilizing agents, and subsequently their anticancer activities were investigated. The synthesized AuNPs were characterized by using ultraviolet–visible spectroscopy (UV–Vis spectroscopy), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). UV–Vis spectroscopy analysis confirmed the characteristics absorption peak of gold, and FTIR findings were highlighted the characteristics boding. SEM and TEM analyses showed that the particles were predominantly spherical in shape. The particles were well dispersed when they were prepared under Hibiscus extracts with average size ∼ 13 nm. An interesting morphology was observed when AuNPs were prepared with curcumin, where particles displayed an interconnected morphology (average size ∼ 18 nm). The anticancer cell activity of AuNPs was studied against human colorectal carcinoma cells (HCT-116) and breast cancer cells (Michigan Cancer Foundation-7 (MCF-7)). The results of anticancer study showed that the treatment of cancer cells with AuNPs decreased the number of cells significantly as compared to control cells. The AuNPs -Hibiscus specimen showed a better inhibiting property than AuNPs -Curcumin, which is attributed to their uniform dispersion and small size.

FORMULATION AND EVALUATION OF POLYHERBAL SHAMPOO CONTAINING EXTRACT OF HIBISCUS, HOLY BASIL AND FENUGREEK

Shampoos has primarily been products that are intended to cleanse the hair and scalp. Herbal preparations always functional and have good activity and very minimal or no adverse effects on performance with synthetic. This study intended to prepare/ formulate and evaluate a complete herbal shampoo containing plant materials used only traditionally. The herbal shampoo prepared containing aqueous extracts of petals of Hibiscus (Hibiscus rosa-sinensis), leaves of Holy basil (Ocimum tenuiflorum) and dried leaves of Fenugreek (Trigonella foenum graecum) prepared by decoction method individually. Various physicochemical parameters such as color, clarity, pH and skin irritability, viscosity, surface tension, foaming ability and stability, and stability studies were studied using suitable procedures. The organoleptic evaluations of the polyherbal shampoo showed good results. The pH of the polyherbal shampoo range to be 5, which was near to skin pH. The viscosity of prepared polyherbal shampoo was found to be 0.0696 poise. The surface tension of prepared polyherbal shampoo was found to be 34.1 dynes/cm respectively.

Green Synthesis of TiO2 Nanoparticles for Pharmaceutical Applications

Nature inspires researcher to carry out new research in the field of science and technology, especially in the field of nanotechnology. In those natural systems Hibiscus rosasinensis plant is one having very important medical properties, Hence used in cough treatments, fertility treatments, henna and it has positive effects on heart disease also. Present research work focused on to synthesis of Titanium dioxide (TiO2) nanoparticles from flower extract of Hibiscus rosasinensis plant using Green synthesis method. The hibiscus flowers were collected and dried under shadow, extract was collected using it. The titanium isopropoxide is used in hibiscus extract and PH value is maintained. The obtained TiO2 nanoparticles have been characterized by X-ray Diffractometer (XRD), Scanning Electron Microscopy (SEM), EDAX& FTIR respectively..

JELLY FOOD CONCENTRATE WITH ENCAPSULATED HIBISCUS EXTRACT

Background. Taking into consideration the intense rhythm of life, the development of technologies for instant food products of increased nutritional value is urgent. Typically, food concentrates for desserts include fruit or fruit and berry fillings and require cooking to prepare ready-made meals. In this case, heat treatment of the mixture (boiling) negatively affects the thermolabile biologically active compounds. The aim of the work was to develop a recipe for instant food jelly concentrates of increased nutritional value based on encapsulated powdery hibiscus extract. Materials and methods. To encapsulate the aqueous-alcoholic extract of hibiscus and obtain a powdered semi-finished product, swelling potato starch was used. Rheological studies were carried out using a "REOTEST-2" rotational viscometer. Results. In order to enrich food concentrates of instant kissel with biologically active substances, we studied a method for extracting dry hibiscus flowers with aqueous-alcoholic solutions of various concentrations. It was found that the extractivity and the transfer of polyphenolic compounds, including anthocyanins, to the extract are improved when a water-alcohol mixture with an ethyl alcohol concentration of 30 % is used as an extractant. For the preparation of a powdery hibiscus extract, modified swelling starch was used, which has the property of swelling in cold water, which makes it possible not to subject the mixture to prolonged heat treatment for preparing a ready-made dish and to preserve the biologically active substances of the hibiscus extract. In addition, this starch is an effective solid carrier that plays a protective role for thermolabile vitamins and bioflavonoids. On the basis of experimental studies, formulations of instant jelly have been developed, which include fructose, powdered hibiscus extract, apple pectin and ascorbic acid. The study of the rheological properties of semi-finished products based on hibiscus extract, as well as ready-made jelly, testifies to the receipt of a finished dessert with a delicate creamy consistency. Conclusion. A method for obtaining a powdery encapsulated hibiscus extract based on swelling potato starch and a composition of a food jelly concentrate using this semi-finished product have been developed. It was found that for the extraction of raw materials it is better to use a water-alcohol mixture with an ethanol content of 30 %, since most of the anthocyanins are converted into the extract under these conditions. The developed semi-finished product of dry hibiscus extract can be used as a thickener, acidifier and colorant in recipes for food concentrates for instant dessert dishes. Due to the use of swelling starch, food concentrates of jelly do not need to be boiled, and the presence of vitamins, organic acids, flavonoids and especially anthocyanins in the hibiscus extract increases the nutritional value of the finished product.

Antioxidant Activity of Phenolic Compounds in Ethanolic Extract of Hibiscus sabdariffa L. on Oxidative Stability of Soybean Oil

Background:The current interest in natural antioxidants from vegetable sources, mainly in bioactive antioxidants, has been increasing in Brazil. The Hibiscus sabdariffa L. is rich in bioactive compounds, besides having antioxidant and antimicrobial properties.Objective:This study aimed to evaluate the antioxidant effect of hibiscus extract on the oxidative stability of soybean oil in an accelerated storage test.Methods:The ethanolic extracts of calyces and hibiscus seeds were evaluated for total phenolic compounds and antioxidant activity using DPPH, FRAP, and β-carotene/linoleic acid. The treatments identified as OS, Tocopherol, Extract, and Mixture, were prepared and submitted to accelerated storage at 60°C. The samples were analyzed on days 0, 6, and 12 for peroxides index, p-anisidine, total oxidation value, oxidative stability, and tocopherols.Results:The extract of calyces of hibiscus presented higher amounts of total phenolic compounds and antioxidant activity. Therefore, it was added to soybean oil. The Extract treatment promoted greater efficiency to inhibit the formation of primary and secondary compounds of lipid oxidation. It provided high oxidative stability to the soybean oil, in addition to greater retention of tocopherols, mainly α- and γ-tocopherol isomers.Conclusion:Among the treatments studied, Extract promoted greater efficiency in the inhibition of the formation of primary and secondary compounds of lipid oxidation, besides providing greater oxidative stability and greater retention of tocopherols during storage.

Chemometric approaches to evaluate the substitution of synthetic food dyes by natural compounds: The case of nanoencapsulated curcumin, spirulina, and hibiscus extracts

Finding natural food coloring options from plant-based sources to substitute artificial dyes is a challenging task because natural dyes often present low water-solubility, not very vibrant hues, and instability due to interactions with food ingredients. Chemometric approaches can be used to evaluate color differences and patterns resulting from natural and synthetic dyes when applied to food systems. Here, the Mixture Design and the Principal Component Analysis (PCA) were applied to evaluate the substitution of the following artificial food dyes: yolk yellow, apricot yellow, strawberry red, and tartrazine by natural dyes (water-soluble curcumin, yellow shade; Hibiscus sabdariffa extract, red shade; Spirulina platensis extract, blue/green shade), in three food simulated systems (phosphate buffer, pH 6.9; yogurt, pH 4.0 and citrate buffer, pH 3.0). The color parameters L*, a*, b*, C* and °h were determined and color difference (ΔE*) with artificial dyes resulted in 11 empirical models. PCA yielded a clear map for the identification of the closely matches natural/artificial dyes for the food simulated systems in three subregions. Furthermore, the antioxidant capacity of the natural dyes was determined by OxHLIA and TBARS. It was possible to make an assessment guide that may be useful for other food systems and dyes.

Development of a PCL-PEO double network colorimetric pH sensor using electrospun fibers containing Hibiscus rosa sinensis extract and silver nanoparticles for food monitoring

Major anthocyanin, cyanidin-3-sophoroside (318.1 mg/mL), and other minor copigments were identified in the ethanol extract of Hibiscus rosa sinensis. The extracts can be coelectrospun with polycaprolactone and polyethylene oxide into fiber mats and were sensitive to pH changes from 1 to 13 with a unique color code (ΔE > 5). The pH sensor was used to monitor shrimp quality under isothermal conditions to obtain the respective activation energy (Ea in kJ/mol) of the sensors’ color-change response (20.2), measured pH (20.6), and trimethylamine nitrogen (24.6), indole (27.1), and total microbial counts (30.8). Together with the Pearson correlation coefficient, the results showed high correlations between the sensors’ color change and other quality parameters (p < 0.001). The regression equation developed by conducting the kinetic analysis was also suitable for predicting shrimp quality at refrigeration temperatures (4–10 °C) and can be used as a marker to monitor shrimp quality by visually inspecting the item condition.

EFFECTS OF HIBISCUS (Hibiscus sabdariffa L.) AND POPPY (Papaver rhoeas L.) EXTRACTS ON DOUGH AND BREAD PROPERTIES THE USAGE OF HIBISCUS AND POPPY IN BREAD

In this study, it was aimed to examine and compare the effects of Hibiscus (Hibiscus sabdariffa L.) and poppy (Papaver rhoeas L.) extracts on some chemical, physical, microbiological and sensory properties of bread dough and bread. The pH, L, b, chroma, hue values of the dough decreased by usage of hibiscus extract, while the a value was increasing. It was determined as the lowest pH was 4.13; L 39.23; b 5.08; chroma was 6.55, hue angle was 54.65 and the highest a value was 7.20. Counts of total mesophilic aerobic bacteria and yeast/mold were found lower in dough with hibiscus extract. Hibiscus extract application gave the lowest specific volume value (2.15 mL/g). In terms of hardness, gumminess and chewiness, the highest values were obtained in hibiscus bread as 24.96 N, 16.13 N and 147.86 mj, respectively. Sensory properties scored of the breads were lower than the control bread.

Impact of electron beam irradiation in potato starch films containing hibiscus aquous extract

The development of starch films containing natural antioxidants is one alternative of active packaging. Starch is a well-studied natural biopolymer that can be used for the development of biodegradable films because it presents a low cost, is easy to obtain and presents good ability to form films. Hibiscus sabdariffa, commonly known as hibiscus, roselle or red sorrel, is an annual herbaceous sub shrub that contains many types of biocompounds, including organic and phenolic acids. The aim of the present work was to determine the influence of electron beam irradiation on potato starch film containing hibiscus extract. The aqueous hibiscus solution was prepared by boiling for 3 min 1% w/ml dehydrated hibiscus flowers in 500 ml deionized water. The film forming solution was prepared by casting (5% potato starch, 3% glycerol as plasticizer and the hibiscus solution) and irradiated in a 1.5 MeV electron beam accelerator Dynamitron II (Radiation Dynamics Inc.), with doses of 0, 20, 40 and 60 kGy. After drying some mechanical properties were measured. The tensile strength of the control films and the irradiated ones was established. There were no significant differences among them. It looks like hibiscus antioxidants were able to prevent the expected starch radiation degradation process caused by radiation generated free radicals.

Exploring the therapeutic potential of Hibiscus rosa sinensis synthesized cobalt oxide (Co3O4-NPs) and magnesium oxide nanoparticles (MgO-NPs).

Herein, we present a green, economic and ecofriendly protocol for synthesis of cobalt oxide (Co3O4-NPs) and magnesium oxide nanoparticles (MgO-NPs) for multifaceted biomedical applications. In the study, a simple aqueous leaf extract of Hibiscus rosa sinensis, was employed for the facile one pot synthesis of Co3O4-NPs and MgO-NPs. The well characterized NPs were explored for multiple biomedical applications including bactericidal activity against urinary tract infection (UTI) isolates, leishmaniasis, larvicidal, antidiabetic antioxidant and biocompatibility studies. Our results showed that both the NPs were highly active against multidrug resistant UTI isolates as compared to traditional antibiotics and induced significant zone of inhibition against Proteus Vulgaris, Pseudomonas Aurigenosa and E.coli. The NPs, in particular Co3O4-NPs also showed significant larvicidal activity against the Aedes Aegypti, the mosquitoes involve in the transmission of Dengue fever. Similarly, excellent leishmanicidal activity was also observed against both the promastigote and amastigote forms of the parasite. Furthermore, the particles also exhibited considerable antidiabetic activity by inhibiting α-amylase and α-glucosidase enzymes. The biosynthesized NPs were found to be excellent antioxidant and biocompatible nanomaterials. Owing to ecofriendly synthesis, non-toxic and biocompatible nature, the Hibiscus rosa sinensis synthesized Co3O4-NPs and MgO-NPs can be exploited as potential candidates for multiple biomedical applications.

USE OF TRADITIONAL HERBS FOR THE FORMULATION OF HERBAL POWDERED SHAMPOOS AND THEIR EVALUATION

The objective of the present research work is to formulate herbal shampoo using traditional herbs like Peppermint; Lemon &amp; Hibiscus extracts as a replacement to synthetic surfactants and carryout a comparative analysis using marketed products. Herbal shampoos formulation was carried out using peppermint, Lemon &amp; Hibiscus extract powders at different concentrations. Formulated shampoos evaluated for organoleptic evaluation, powder characteristics, pH, dirt dispersion, detergency, cleaning action, foaming ability and its stability and conditioning performance. Design Expert Statistical software used to optimize the formulations and to understand main effects, interaction effects on the properties of shampoos. All the herbal powder shampoo formulations pH closer to the skin pH. The shampoos containing higher concentration of peppermint shown higher detergency, lemon as well as peppermint showed significant effect on the foaming capacity and cleaning action and similar to marketed formulations. Higher quantity of Hibiscus concentration shown better conditioning behaviour. The formulated shampoos were uniform, denser and stable similar as that of marketed shampoo. Based on the Design expert statistical evaluation of results, formulations containing 15% of Peppermint, 1% - 3% of Lemon and 12.5% – 14.5% of Hibiscus herbal powder shampoos shown better performance compared with marketed formulations. PS19, PS20 &amp; PS21 formulations were selected as the best formulations based on physicochemical properties. The selected herbal powder shampoos has an excellent cleansing, detergency, conditioning and foaming effect, is suitable for regular hair and has acceptable pH and organoleptic stability characteristics.

Effect of thermal and ultrasound processes on some quality characteristics of sage and hibiscus extracts

Bu çalışmada termal ve ultrases uygulamalarının adaçayı ve hibiskus ekstraktlarının bazı kalite özellikleri üzerine etkisi araştırılmıştır. Bu amaçla 85°C’de su banyosunda, ultrasonik banyoda (&amp;lt;40°C, 0.031 W mL-1 Akustik Güç Yoğunluğu) ve problu ultrases sisteminde (&amp;lt;40°C, 1.337 W mL-1 Akustik Güç Yoğunluğu) uygulamalar gerçekleştirilmiştir. Uygulama sürecinde 5, 10, 15 ve 20 dk zaman aralıkları ile örnekleme yapılmış ve örneklerde pH, iletkenlik, renk, bulanıklık ve toplam fenolik madde içeriği analizleri yapılmıştır. Adaçayı (1.3 °Bx) ekstraktlarının pH, iletkenlik ve toplam fenolik madde içerikleri sırasıyla 5.66-5.73, 1.61-1.63 ms cm-1 ve 2.58-2.71 g L-1 GAE arasında belirlenirken, hibiskus ekstraktlarında bu değerler sırasıyla 2.28-2.41, 4.05-4.16 ms cm-1 ve 0.80-0.84 g L-1 GAE arasında değişim göstermiştir. Uygulamaların genel olarak bulanıklık değeri dışında önemli bir değişime neden olmadığı gözlenmiştir. Problu ultrases sistemi ile 20 dakikalık uygulamadan sonra adaçayı ekstraktlarında bulanıklık değeri 117 NTU'dan 230 NTU'ya yükselirken, bu değer hibiskus ekstraktlarında 58.95 NTU'dan 153.6 NTU'ya yükselmiştir.

Thermal degradation kinetics and physicochemical analysis of the freeze-dried hibiscus flower extract (Hibiscus sabdariffa)

The goal of this research was to evaluate the kinetics of thermal degradation of the hibiscus extracts powder at different temperatures and to characterize physicochemically the freeze-dried aqueous extract of the hibiscus flower (Hibiscus sabdariffa) with different concentrations of maltodextrin (0, 5, 10 and 15%). The analyzed parameters were: water content, total soluble solids, titratable acidity, pH, ash, solubility, hygroscopicity, bulk and tapped density, the flowability (Carr index) and cohesiveness (Hausner ratio), lightness (L*) and intensity of red (a*) and yellow (b*). The degradation kinetics was analyzed by the determination of bioactive compounds of flavonoids, anthocyanins and color appearance parameters (lightness, intensity of red and yellow, chroma and hue angle). The increase in maltodextrin concentration resulted in increases of solubility, soluble solids content, pH and color appearance parameters; as the parameters of bulk and tapped density, hygroscopicity, water content, ash and acidity presented decreases as the proportion of additive increased, showing good flowability and low to medium cohesion. Regarding the degradation kinetics, the maltodextrin was effective in the preservation of anthocyanins and flavonoids of the freeze-dried hibiscus flower up to the temperature of 50 °C. Therefore, this work resulted in the preparation of a product derived from the freeze-drying process with and without additives and with preserved sensory attributes of high quality

Use of natural plant extracts as a novel microbiological quality indicator in raw milk: An alternative for resazurin dye reduction method

In the present study, we propose a novel field-scale analytical tool for rapid screening of microbiological quality in raw milk using aqueous extracts of plant materials, i.e. flowers (e.g. Hibiscus rosa-sinensis L. and Clitoria ternatea), taproots (e.g. Beta vulgaris) and pricklypears (e.g. Opuntia dillenii). For each plant extract, the colour changes in raw milk were evaluated between 4.5 and 6.5 pH against the resazurin dye as a control. The plant anthocyanin content in each extract was analyzed by the differential pH method using a spectrophotometer. The Hibiscus rosa-sinensis flower extract was opted to further test since it had a pH-sensitive colour change (6.5; maroon to 6.2; light-pink) compared to other plant extracts, which did not indicate a noticeable colour variation with pH. Anthocyanin content of the Hibiscus extract was 0.59 g/mL. The novel method showed high linearity (R2 = 0.95), 100% accuracy and greater repeatability with an intermediate level of precision. The limit of quantification and detection was 0.46 and 0.15 g/mL, respectively. In conclusion, we demonstrated the potential in using water extract of Hibiscus rosa-sinensis L. flowers as an alternative to the resazurin dye reduction method for rapid and accurate microbiological quality control for raw milk procurement in remote areas.

The effect of plant extracts on antioxidant potential, microbial and sensory attributes of stirred yoghurt

The aim of this study was to use various plants to increase the functional properties of yoghurt. The ethanol extracts of three different plant (Mentha piperita L., Ocimum basilicum L., and Hibiscus sabdariffa L.) extracts were added to the stirred type yoghurts at different ratios (0.1%, 0.3% and 0.5%). The pH values, colour values, antioxidant activity, microbial and sensory attributes of yoghurt were evaluated on the storage days of 0, 7, 14, 21, and 28. The lowest pH values were found at the beginning (4.29) and at the end (3.95) of the storage period in samples containing 0.5% hibiscus extract. The addition of plant extracts in amounts of 0.3% and higher decreased the lightness (L*) value of yoghurt (p&lt;0.05), and the maximum decrease was found in yoghurt samples containing 0.5% hibiscus ethanol extract. The concentrations of added mint and basil extracts increased the yellowness (b*) value (p&lt;0.05), while the addition of hibiscus extract significantly increased the redness value (p&lt;0.05). Hibiscus ethanol extract significantly reduced the growth of total aerobic mesophilic bacteria (TAMB), lactic acid bacteria (LAB) and Lactococcus/ Streptococcus bacteria (p&lt;0.05). The antioxidant activity of all samples increased with adding plant extracts. According to the results of sensory analysis, the addition of 0.1% plant extracts to yoghurts rated higher scores than that of the control sample, but the addition of 0.3% and 0.5% ethanol extracts negatively affected the sensory properties. It can be concluded that adding plant extracts had a positive effect on the sensory and functional properties of yoghurt.