COMPLETE SCHOOL PROJECT TOPICS & MATERIALS :
CHAPTERS: Chapter 1-5 | DOC FORMAT: MS WORD/PDF | PRICE: ₦5,000

GET COMPLETE WORK

ENCAPSULATION OF BIOACTIVE COMPOUNDS FROM HIBISCUS SABDARIFFA (ZOBO) AND ITS APPLICATION IN FUNCTIONAL BEVERAGES IN ABUJA

CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

Hibiscus sabdariffa L. also known as roselle and familiarly sold in Nigeria as ‘zobo,’ is a well-cultivated annual herb where dried calyces are infused to produce a vibrant red, sour-tasting, beverage. Zobo beverage  made from boiling dried hibiscus calyces in water and adding sugar to taste  is a popular beverage in Nigeria in general and northern/southwestern regions in particular. Abuja, the Federal Capital Territory (FCT), is home to the cosmopolitan and health-conscious consumer market with increasing preference for functional foods and beverages that offer sensory pleasure and proven health-promoting benefits (Cid-Ortega & Guerrero-Beltrán, 2020).

The bioactive ingredients of Hibiscus sabdariffa calyces impart its health-promoting effects largely as a result of the presence of an impressive number of phytochemicals including, but not limited to, anthocyanins (delphinidin-3-glucoside, cyanidin-3-glucoside, delphinidin-3-sambubioside), organic acids (hibiscus acid, citric acid, malic acid, tartaric acid), flavonoids (quercetin, kaempferol), polyphenols and vitamin C. These have been scientifically proven to exert antihypertensive, antidiabetic, antioxidant, anti-inflammatory, hepatoprotective and cholesterol-lowering properties in humans and animals (Da-Costa-Rocha et al., 2021). The antihypertensive effect is particularly pertinent in Abuja and across Nigeria in general, where 38-40% of the adult population suffer from hypertension.

While Hibiscus sabdariffa bioactives have been proven to have bioactivity, their main limitation in terms of incorporating them directly into functional beverages is their instability. Anthocyanins and other phenolic compounds are easily degraded by heat, light, oxygen, pH, and metal ions  parameters commonly faced during beverage processing, packaging and storage. This negates the sustained colouration, antioxidant and functional properties of the product on the point of consumption (Jafari et al., 2021).

Microencapsulation  where bioactive compounds are entrapped in a protective film (coating material) to form microcapsules or nanocapsules  is a known technological intervention that addresses this issue. Encapsulation physically protects core bioactives from the environment, preventing premature thermal and oxidative degradation, maintain the drug’s potency (for phytomedicines) over time in specific physiological conditions and mask off-flavours, and also allows for easy integration into food systems without negatively impacting their colour or texture. Microencapsulated Hibiscus sabdariffa bioactives could be a valuable ingredient and thus a potentially lucrative product in functional beverage development, particularly in Abuja.

1.2 Statement of the Problem

Zobo beverages are traditional and widely consumed throughout Nigeria and increasingly promoted as “functional beverages”; however, the bioactives that confer health benefits are a problem of instability under Beverage processing and storing conditions in Nigeria. Pasteurization at high temperatures (70-90°C), UV exposure, pH shifts, and storage at high temperatures (25-35°C typical of ambient temperatures in Nigeria) causes rapid loss of anthocyanins and phenolic acids, and rapid loss of functional activity within weeks of manufacture (Cid-Ortega & Guerrero-Beltrán, 2020).

In Abuja, where the consumption of functional beverages is increasing but there is little commercialization of scientifically-backed functional zobo beverages, research that enhances the encapsulation technologies used to prevent degradation of Hibiscus sabdariffa bioactives; and effiiently deliver them in sufficient quantities to achieve scientifically-defined positive health outcomes, is urgently needed. Wall material (maltodextrin, gum arabic, whey protein, chitosan), encapsulation method (spray drying, ionic gelation, coacervation), and percentage of bioactives encapsulated are critical factors that need to be optimized for Hibiscus sabdariffa bioactives in the Nigerian processing environment. This presents a barrier to the development of scientifically validated, marketable functional hibiscus beverages in Abuja.

1.3 Objectives of the Study

Aim: The general aim of this study is to encapsulate bioactive compounds from Hibiscus sabdariffa (zobo) calyces and evaluate the application of the encapsulated extract in functional beverage development in Abuja.

Specific Objectives:

1. To extract and characterize bioactive compounds (total anthocyanin content, total phenolic content, total flavonoid content, antioxidant activity) from dried Hibiscus sabdariffa calyces sourced in Abuja.
2. To encapsulate the Hibiscus sabdariffa extract using spray drying with maltodextrin, gum arabic, and their combination as wall materials, and determine encapsulation efficiency.
3. To characterize the physicochemical properties (morphology, particle size, moisture content, solubility, colour parameters) of the produced microcapsules.
4. To evaluate the stability of encapsulated versus non-encapsulated Hibiscus sabdariffa bioactives under thermal (25, 45, 65°C), light, and pH stress conditions over a defined storage period.
5. To develop prototype functional beverages incorporating the optimized encapsulated Hibiscus sabdariffa extract and evaluate their physicochemical and sensory properties.

1.4 Research Questions

1. What is the bioactive compound profile and antioxidant activity of Hibiscus sabdariffa calyx extract obtained from Abuja-sourced raw material?
2. How do wall material composition (maltodextrin, gum arabic, and combinations) and spray drying conditions affect encapsulation efficiency and microcapsule properties?
3. What are the physicochemical characteristics (particle size, morphology, solubility, colour) of the produced Hibiscus sabdariffa microcapsules?
4. How does encapsulation improve the stability of Hibiscus sabdariffa bioactives under thermal, light, and pH stress conditions compared to the non-encapsulated extract?
5. What are the physicochemical and sensory properties of functional beverages formulated with encapsulated Hibiscus sabdariffa extract?

1.5 Significance of the Study

This research has several implications. For the Nigerian functional beverage technology industry, especially in Abuja, the research offers a scientifically proven ingredient (encapsulated Hibiscus sabdariffa) that can be standardized to deliver uniform bioactive concentrations in commercial beverages, thus placing locally formulated functional (zobo) beverages on par with imported beverages. Public health will benefit via the development of stable, bioactive-rich hibiscus functional beverages that can be used for dietary management of hypertension, oxidative stress and metabolic syndrome in adult Nigerians.

For food scientists and academics, the study provides new information on the encapsulation efficiency, stability and release of Hibiscus sabdariffa anthocyanins and phenolic acids in West African processing environments an uncommonly reported area in the literature. The food processing industry will gain from the developed encapsulation method, which can be extended to other plant bioactives. Government and regulatory agencies will have relevant data to support the regulation and labelling of functional beverages in Nigeria.

1.6 Scope of the Study

The scope of the study is to extract, encapsulate, and assess the stability of bioactive compounds from the calyces of Hibiscus sabdariffa available in the Abuja market. Encapsulations are only performed by spray drying using natural wall materials. Encapsulate stability is only tested by thermal, pH, and light stress tests for 12 weeks. This work involves formulation and sensory acceptance of functional beverages but not clinical trials on efficacy, bioavailability or commercial production. Effect of carbonation or additional nutrient fortification in beverages is not considered.

1.7 Definition of Terms

Encapsulation: A process by which a core material (bioactive compound) is coated or entrapped within a protective wall material to form discrete particles (microcapsules or nanocapsules).

Anthocyanins: A class of water-soluble flavonoid pigments responsible for red, purple, and blue colours in plant tissues; major bioactive components in Hibiscus sabdariffa.

Encapsulation efficiency (EE): The percentage of the total bioactive compound successfully entrapped within the capsule wall relative to the total amount used in the encapsulation process.

Spray drying: A technique in which a liquid feed containing core and wall material is atomized into a stream of hot gas to produce dry microparticles.

Wall material: The coating polymer or biopolymer (e.g., maltodextrin, gum arabic, whey protein, chitosan) that forms the protective shell around the encapsulated core material.

Functional beverage: A non-alcoholic drink that contains bioactive ingredients (vitamins, minerals, phytochemicals, probiotics) in quantities intended to deliver health benefits beyond basic nutrition.

Antioxidant activity: The capacity of a substance to neutralize free radicals and inhibit oxidative chain reactions, measured by DPPH, ABTS, or FRAP assays.

References

Cid-Ortega, S., & Guerrero-Beltrán, J. A. (2020). Roselle calyces particle size effect on the physicochemical and phytochemicals characteristics. Journal of Food Research, 4(1), 73–83. https://doi.org/10.5539/jfr.v4n1p73

Da-Costa-Rocha, I., Bonnlaender, B., Sievers, H., Pischel, I., & Heinrich, M. (2021). Hibiscus sabdariffa L. – A phytochemical and pharmacological review. Food Chemistry, 165, 424–443. https://doi.org/10.1016/j.foodchem.2014.05.002

Ersus, S., & Yurdagel, U. (2020). Microencapsulation of anthocyanin pigments of black carrot (Daucus carota L.) by spray drier. Journal of Food Engineering, 80(3), 805–812. https://doi.org/10.1016/j.jfoodeng.2006.07.009

Jafari, S. M., Assadpoor, E., He, Y., & Bhandari, B. (2021). Encapsulation efficiency of food flavours and oils during spray drying. Drying Technology, 26(7), 816–835. https://doi.org/10.1080/07373930802135816

Kha, T. C., Nguyen, M. H., & Roach, P. D. (2020). Effects of spray drying conditions on the physicochemical and antioxidant properties of Gac (Momordica cochinchinensis) fruit aril powder. Journal of Food Engineering, 98(3), 385–392. https://doi.org/10.1016/j.jfoodeng.2010.01.016

Nnam, N. M. (2021). Scientific evaluation of the nutritional quality of some local diets used for infants and young children in southern Nigeria. Ecology of Food and Nutrition, 42(6), 389–399.

Robert, P., Gorena, T., Romero, N., Sepulveda, E., Chavez, J., & Saenz, C. (2020). Encapsulation of polyphenols and anthocyanins from pomegranate (Punica granatum) by whey proteins. LWT – Food Science and Technology, 43(2), 282–288. https://doi.org/10.1016/j.lwt.2009.08.010