Determination of Sugars, Amino Acids, pH and Alcohol in Bamboo Beverage from Southern Highlands, Tanzania

The amounts of sugars and amino acids play significant roles in defining the fermentation process and quantifying the alcohol levels in beverages, while pH affects the biological stability, colour, oxidation rate, and protein stability of alcoholic beverages. This study investigated the sugar content, amino acids, alcohol levels, and pH of bamboo beverage from Tanzania's southern highlands. During storage, the sugars significantly decreased (p < 0.05), especially when kept at room temperature from 52.96 to 0.00 (source 1), 53.35 to 0.00 (source 2) and 53.57 to 0.00 (source 3) g/L for fructose, from 47.93 to 14.78 (source 1), 47.23 to 14.91 (source 2) and 47.61 to 14.77 (source 3) g/L for glucose, and from 0.40 to 0.00 (source 1), 0.36 to 0.00 (source 2) and 0.37 to 0.00 (source 3) g/L for sucrose after six days of storage. A total of 15 amino acids were determined from the bamboo beverage with tyrosine being the most prevalent (597.68 mg/L for source 1, 599.44 mg/L for source 2 and 597.83 mg/L for source 3), followed by valine (261.13 mg/L for source 1, 261.24 mg/L for source 2 and 262.54 mg/L for source 3), threonine (76.69 mg/L for source 1, 76.91 mg/L for source 2 and 77.13 mg/L for source 3), and serine (66.37 mg/L for source 1, 67.23 mg/L for source 2 and 66.68 mg/L for source 3). After six days of storage at room temperature, there was a significant decrease in pH from 4.04 to 3.63. Alcohol content ranged from 3.11 to 9.05% v/v at the room temperature storage. These results might facilitate the optimal use of bamboo beverages, which have been neglected due to lack of scientific information such as amino acid and sugar levels. Keywords:  Bamboo beverage, ulanzi, amino acids, sugars, alcohol conten

Physico-chemical Properties of Mechanically Extracted Banana Juice at Different Ripening Stages

This paper presents the findings of a study on physico-chemical properties of low viscosity banana juice from five banana cultivars: Pisang Awak (PSA) an ABB genome, Yangambi km5 (YKM5) an AAA genome and cultivars from AAA-EA genome, namely Mbilabile, Ndeshi and Mlonga. Low viscosity banana juice was extracted using improved mechanical method at five ripening stages. The physico-chemical properties significantly varied according to cultivars and ripening stages (p < 0.05). Yields, total soluble solids (TSS), titratable acidity (TA) and pH were in the range of 19.50–74.03%, 7.33–27.64 ºBrix, 0.37–0.76% malic acid equivalent and 4.09–4.70, respectively. Yields decreased in the order of Mbilabile > Ndeshi > Mlonga > YKM5 > PSA whereas the total soluble solids increased as follows Mlonga < Mbilabile < Ndeshi < YKM5 < PSA. Furthermore, ashes and mineral contents decreased with ripening stages whereas the low viscosity banana juice was rich in potassium and magnesium. Finally, the study recommends stage 5 of the ripeness as ideal for producing low viscosity banana juice. Keywords: Mechanical extraction, Banana cultivar, Ripening stage, Tannin, Banana juic

Chemical Composition and Bioactive Potential of Extracts from Diospyros capricornuta F. White against Aspergillus flavus and Aspergillus parasiticus

Diospyros capricornuta is an endemic species widely distributed along the coast of Tanzania that is used as food condiments and traditional medicine. The chemical compositions of Diospyros capricornuta leaves, stem-bark, and root-bark extracts; and their bioactive potentials against Aspergillus flavus and Aspergillus parasiticus were investigated. The leaves, stem-bark, and root-bark samples of D. capricornuta were extracted using Soxhlet apparatus and the resultant extracts were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). A total of 14 compounds were identified from the extracts, whereby 2,4-di-tert-butylphenol was the most abundant compound in all extracts. The growth and aflatoxin production inhibitions against A. flavus and A. parasiticus were determined via antifungal and antiaflatoxigenic bioassays of the extracts at the concentrations of 0.0, 62.5, 125.0, and 250.0 µg/mL using a poisoned-food method. The High-Performance Liquid Chromatography (HPLC) technique was used to quantify the aflatoxins after bioassays to evaluate aflatoxin inhibitions. The stem-bark extracts at the highest dose of 250.0 µg/mL inhibited aflatoxin production by A. flavus for over 99% and A. parasiticus for over 94%. Overall, the results show that the leaves, stem-bark, and root-bark extracts of D. capricornuta are potential inhibitors against A. flavus and A. parasiticus-the producers of aflatoxins. Keywords: Diospyros capricornuta; Growth inhibitions; Aflatoxin inhibitions; Aspergillus flavus; and Aspergillus parasiticus

Evaluation of Natural Antifungal Compounds from Artemisia afra and its Effectiveness on Prevention of Aflatoxins

Artemisia afra is a medicinal plant with antimicrobial activities, known to treat tuberculosis, measles, cough, and influenza. In consequence, its applications have increasingly become pivotal to control various microbes which cause different diseases. This study therefore, evaluated the chemical composition and the antifungal activity of A. afra essential oil. The extraction of essential oil was done using steam distillation. The essential oil chemical composition was analysed by GC-MS. The analysis revealed 19 compounds from A. afra. The main compounds were borneol (71.529%), terpinen-4-ol (8.582%), β-thujone (3.283%), β-terpineol (2.590%), α-terpineol (1.791%), chrysanthenone (1.507%), myrtenal (1.393%), eucalyptol (1,8-cineole) (1.263%), cis-sabinene hydrate (1.172%) and trans-carane, 4,5-epoxy (1.088%). The growth and aflatoxin production inhibitions against A. flavus were determined via antifungal and antiaflatoxigenic bioassays of the A. afra essential oil at the concentration range of 10–50 µL/mL using a poisoned-food method. The quantification of the aflatoxins production was carried out using high-performance liquid chromatography. The antifungal activity of A. afra essential oil was effective against A. flavus with growth inhibition of 99.97–99.99% and controlled aflatoxins production by 99.25–99.63%. The results indicated that A. afra essential oil can become an alternative natural fungicide for the control of A. flavus growth and aflatoxins production. Keywords: Artemisia afra; essential oil; A. flavus; aflatoxins; GC-M

Development of Biodegradable Food Packaging Materials from Agricultural Biomass

This study utilised maize husk fibres and pulp to prepare a biocomposite fabric for foodpackaging. The optimum conditions for extracting maize husk fibres were determinedexperimentally to be 5 g/l of sodium hydroxide concentration at 100 °C for 60 minutes and liquor ratio of 1:20. The fabric was manufactured by solution casting of maize husk pulp on a web prepared by aligning maize husk and sisal fibres using a deckle and frame. The sisal fibre content was varied from 5 to 50% at ratios ranging from 95:5 to 50:50 (maize: sisal fibres). The biodegradable fabric was characterised using three mechanical properties: tear strength, tensile strength, and abrasion resistance. The tear strength ranged from 0.79 MPa to 3.93 MPa whereas the tensile strength ranged from 13.35 MPa to 56.46 MPa, which conforms to the data available from literature. Abrasion tests verified that there was no mass loss at 5,000, 10,000 and 15,000 cycles. Overall, the study findings show that maize husk fibres can replace up to 80% of sisalfibres in materials for food packaging applications without compromising their quality. Keywords: Maize husk fibre, biocomposite, sisal fibres, food packaging