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The study aimed to focus on the effect of the processing parameters on the physicochemical properties of oil from roselle seed.

Fine and coarse samples of the ground roselle seeds were conditioned to the moisture contents of 4.4‐10.4 per cent and 5.14‐11.14 per cent. Oil was expressed at applied pressures of 15‐37.5 MPa with 7.5 MPa interval using hydraulic oil extractor for between 10‐40 min. at increment of 10 min. and at the heating temperatures of 80, 90, 100 and 110°C over a period of 15‐30 min. at an increment of 5 min. All the physicochemical properties were determined using AOAC and AOCS methods [AOAC, 1984; AOCS, 1994].

The free fatty acid, peroxide values and the colour intensity of the oil were affected by the processing parameters; while saponification value, viscosity, specific gravity, refractive index and the iodine value of the oil were not affected by the expression parameters.

Processing parameters were found to affect the quality attributes of free fatty acid, peroxide values and the colour intensity of the oil.

The purpose of this paper is to determine the physicochemical properties of oil produced from Roselle seeds.

The oil was produced from the seeds by mechanical expression and the physicochemical properties of the oil determined using the AOAC methods.

The values of the physicochemical properties of oil from Roselle seed are saponification value 126.2, iodine value 111.2, viscosity 22.5 cp, refractive index 1.4472 and specific gravity 0.9558. The peroxide value varied between 6.0‐9.3 and 5.9‐9.0; and free fatty acid, 0.435‐2.300 and 0.510‐3.311 for fine and coarse samples, respectively. These values compared favourably with standard values, indicating that the oil extracted is edible.

The properties are useful in determining the suitability of the oil from the Roselle seeds as edible oil or for other industrial purposes.

This study aims to investigate some physicochemical characteristics of Hildegardia barteri seed oils obtained by cold-pressing and solvent extraction procedures.

Crude oil samples were obtained from the kernels by cold pressing and solvent extraction. The physicochemical properties of the oil samples were investigated according to the standard procedures in published works of literature.

The oil yield was 55.7 and 97 per cent for cold-pressed kariya seed oil (CPKSO) and solvent-extracted kariya seed oil (SEKSO), respectively. Specific gravities, refractive indices, viscosities, iodine value, saponification value, peroxide value and acid value were 0.8742 and 0.9036; 1.4629 and 1.4584; 75.93 and 74.90 mPa.s; 55.78 and 53.56 g of I2/100g of oil; 249.76 and 253.90 mg KOH/g; 4.86 and 5.02 meq KOH/g; 2.12 and 2.09 mg KOH/g of oil for CPKSO and SEKSO, respectively. The physicochemical characteristics of kariya seed oil were not significantly affected by extraction method. The fatty acid profiles of CPKSO and SEKSO showed that the two oil samples contain 24.2 and 23.7, 31.3 and 29.3, 23.2 and 23.7 and 19.6 and 21.3 per cent of myristic, palmitic, stearic and linolenic acids, respectively. Lauric and oleic acids were present in very little proportions of 0.3 and 0.41; and 0.01 and 0.03 per cent, respectively, whereas linoleic acid was 1.4 per cent for the two oil samples. Significant differences in fatty acid profiles were observed for lauric, palmitic and linolenic acids (p = 0.05). Saturated and unsaturated fatty acids were about 79.0 and 77.11 per cent and 21.01 and 22.73 per cent for CPKSO and SEKSO, respectively.

This work promotes H. barteri tree beyond its use as a mere ornamental plant. The non-conventional seed oil it produces may find relevance in the food or biofuels industry subject to further investigation.

This study is the first to document the extraction and physicochemical properties of kariya seed oils.

This paper aims at examining the potentiality of using Hibiscus sabdariffa L. calyces’ (Hs) aqueous extract to remove soot stains from the surface of fire-damaged silver gelatin prints. It further studies the cleaning efficiency and impact of both a contact method and a noncontact method with argon dielectric barrier discharge plasma (DBD Ar. plasma) on the different properties of silver gelatin prints. Accordingly, it prompts using economic, eco-friendly materials and methods in the photograph conservation field.

To achieve the aims of this paper, four silver gelatin prints were stained with soot and treated with the Hs aqueous extract as a contact method and DBD Ar. plasma combined with the aqueous extract as a noncontact method. The assessment was carried out using digital microscopy, atomic force microscopy and spectrophotometer to study the efficiency of the tested treatments and their impact on the surface of the photographs. Fourier transform infrared was used to monitor the state of the binder after cleaning. Furthermore, the pH and the mechanical properties were measured.

The contact method resulted in lower concentrations of Hs extract that efficiently cleaned the surface without causing any stains or damage to the treated photographs. The noncontact method (plasma with an aqueous extract) proved to be less effective in cleaning and made the binder more susceptible to deterioration.

This paper reveals the success of Hs aqueous extract in cleaning soot on vulnerable photographs' surfaces.

The amount of food wasted every year is 1.3 billion metric tonne (MT), out of which 0.5 billion MT is contributed by the fruits processing industries. The waste includes by-products such as peels, pomace and seeds and is a good source of bioactive compounds like phenolic compounds, flavonoids, pectin lipids and dietary fibres. Hence, the purpose of the present study is to review the novel extraction techniques used for the extraction of the bio active compounds from food waste for the selection of suitable extraction method.

Novel extraction techniques such as ultrasound-assisted extraction, microwave-assisted extraction, enzyme-assisted extraction, supercritical fluid extraction, pulsed electric field extraction and pressurized liquid extraction have emerged to overcome the drawbacks and constraints of conventional extraction techniques. Hence, this study is focussed on novel extraction techniques, their limitations and optimization for the extraction of bioactive compounds from fruit and vegetable waste.

This study presents a comprehensive review on the novel extraction processes that have been adopted for the extraction of bioactive compounds from food waste. This paper also summarizes bioactive compounds' optimum extraction condition from various food waste using novel extraction techniques.

Food waste is rich in bioactive compounds, and its efficient extraction may add value to the food processing industries. Hence, compressive analysis is needed to overcome the problem associated with the extraction and selection of suitable extraction techniques.

Selection of a suitable extraction method will not only add value to food waste but also reduce waste dumping and the cost of bioactive compounds.

This paper presents the research progress on the extraction of bioactive active compounds from food waste using novel extraction techniques.

The physico‐chemical characteristics of roselle from Malaysia were studied. The parameters analysed included size, weight, pH, titratable acidity, soluble solids, anthocyanin contents, organic acids and sugars. Succinic and oxalic acids were the predominant organic acids found in roselle while glucose was the major sugar present. The present study was also conducted to determine and quantify the most biologically effective natural antioxidants present in roselle. Ascorbic acid, β‐carotene and lycopene, were separated, identified and quantified by HPLC. The amounts of ascorbic acid, β‐carotene and lycopene contents were 141.09mg/100g, 1.88mg/100g and 164.34μg/100g, respectively. The individual anthocyanin in roselle was characterised by TLC and HPLC. Delphinidin‐3‐sambubioside and cyanidin‐3‐sambubioside were the main anthocyanin present in roselle.

The purpose of this study is to investigate the effect of roselle flower extract and date palm pollen on the nutritional and sensory qualities of date palm spathe beverage (DPSB).

The nutritional composition and sensorial quality of the date palm spathe-based beverage were evaluated. The product was fortified with different concentrations (1 per cent and 5 per cent) of roselle flowers and 1 per cent date palm pollen grains.

Generally, fortification of the DPSB with roselle flowers only or the combination of roselle flowers and date palm pollen grains significantly affected the nutritional and sensory properties of the products. The total dissolved solids, turbidity and total contents of proteins; fats; carbohydrates; vitamins A, E and C; iron; nickel and copper were highest in the DPSB fortified with a mixture of 1 per cent roselle flower extract and 1 per cent pollen grains and lowest in the DPSB supplemented with 1 per cent roselle flower extract. The manganese and selenium contents were both highest and lowest in DPSB supplemented with 5 per cent and 1 per cent roselle flower extract, respectively. Antioxidant activity was highest in DPSB supplemented with the 5 per cent roselle flower extract and lowest in unfortified DPSB. Boron, molybdenum and zinc contents were highest in unfortified DPSB. All sensory attributes were highest in both the unfortified DPSB and that fortified with 1 per cent roselle flower extract.

While fortification with a combination of 1 per cent roselle flower extract and 1 per cent date palm pollen grains improved the nutritional quality of the DPSB, it negatively affected the sensory attributes of the products.

The purpose of this study is to evaluate the effects of partial or total substitution of milk fat by various levels of jojoba oil on the nutritional, physicochemical and sensory properties of Domiati cheese during cold storage at 6°C for 45 days.

The fat percentage of milk used for cheese manufacture was standardized to 4% fat. Five formulas were produced by replacing milk fat with 0%, 25%, 50%, 75% and 100% of jojoba oil, respectively. The physicochemical and sensory properties of cheese samples at 0, 15, 30 and 45th days of cold store were evaluated.

No significant differences in moisture, fat, protein and acidity values amongst the control samples and those samples supplemented with different concentrations of jojoba oil. Significant differences (p = 0.05) in total volatile fatty acids were detected amongst experimental cheese samples. The highest values were recorded for control sample containing 100% milk fat, while the lowest values were recorded for cheese sample containing 100% jojoba oil (p = 0.05). Total nitrogen (TN), water-soluble nitrogen (WSN) and trichloroacetic acid soluble nitrogen (TCA-SN) levels of experimental cheeses were nearly same as for control. The results of fatty acids profile showed that jojoba oil has a unique structure of straight monounsaturated alcohols. Significantly (p = 0.05), the highest cholesterol content was recorded for control sample containing 100% milk fat; however, the lowest (p = 0.05) value was recorded for cheese sample containing 100% jojoba oil. At the end time of storage period, control sample manufactured with 100% milk fat had the highest (p = 0.05) values of free fatty acids, peroxide and thiobarbituric acid, while the lowest values were recorded for cheese sample with 100% jojoba oil as a source of fat. The sensory evaluation results demonstrated that blending milk fat with jojoba oil improved the sensory properties of Domiati cheese.

It is concluded that substitution of 25%, 50%, 75% and 100% of milk fat by equal amounts of jojoba oil enhanced the nutritional and sensory characteristics of Domiati cheese.

It is concluded that Domiati cheese formulated with substitution of 25%, 50%, 75% and 100% of milk fat by equal amounts of jojoba oil enhanced the nutritional characteristics and improved the sensory properties of produced cheese.

The purpose of this paper is to develop a new water based coating system composed of poly(acrylamide‐co‐acrylic acid) and anthocyanin colourant extracted from Hibiscus sabdariffa L. and characterise the system.

Anthocyanin from Hibiscus sabdariffa L. (roselle) calyxes was extracted using optimised water extraction method with ratio of calyxes to water being 1:2. UV‐Vis absorption spectroscopy was conducted on the anthocyanin extract to monitor its degradation. Poly(acrylamide‐co‐acrylic acid) was mixed with the extracted anthocyanin solution in two different weight ratios. The mixtures were coated on glass substrate and let to cure for approximately one day. FTIR spectroscopy was conducted on the samples to determine their functional groups and identify the compounds in the samples. Cross hatch test was performed on the samples to determine the adhesion properties. Thermal degradation of the samples was determined through thermogravimetric analysis. Surface roughness of the samples was studied by atomic force microscopy. Colour stability was determined before and after UV irradiation.

Anthocyanin pigment from roselle extracted with water was found to be stable with 6.0 per cent drop in absorbance value over the 15 day period. The reaction rate was found to be 0.000181 h⁻¹, and the half life was calculated to be 3,850 hours. Better adhesion of the samples to the glass substrate was due to the higher concentration of poly(acrylamide‐co‐acrylic acid). Thermogravimetric analysis revealed similar thermal stability of the samples. Surface roughness study revealed that sample with higher anthocyanin content has higher surface roughness. Colour stability of the 20PBR was found to be better than 10PBR.

Usage of poly(acrylamide‐co‐acrylic acid) as coating is limited by its weak water resistance property. Improvement could be made in this direction for future applications.

Mixture of water‐based polymer and anthocyanin colourant from roselle has been developed into coating for the first time. Commercialisation is possible if more research is conducted towards water resistance property of poly(acrylamide‐co‐acrylic acid), storage condition for the pigment and coating, and mass production of the pigment.

Incorporation of anthocyanin pigment into water based coating is the first of its kind.

Literature has consistently reported that coloured plants are rich in dietary bioactive compounds. Therefore, this study aims to compare the total phenolic content and antioxidant activities in selected coloured plants (blue butterfly pea flower, roselle calyx, yellow bell pepper and purple sweet potato).

Total Phenolic Content (TPC) was determined using Folin–Ciocalteu assay, while antioxidant activities were evaluated using 2,2-dophenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging, Ferric Reducing Antioxidant Power (FRAP) and Trolox Equivalent Antioxidant Capacity (TEAC) assays.

TPC was reported from 273.15 ± 19.57 µg GAE/g DW (blue butterfly pea flower extract) to 363.10 ± 7.94 µg GAE/g DW (roselle calyx extract). Antioxidant activities as determined by DPPH assay ranged from 17.26 ± 0.06% (purple sweet potato extract) to 83.38 ± 1.04% (yellow bell pepper extract); while for FRAP assay was 4.92 ± 0.18 mg Fe (II)/g DW (purple sweet potato extract) to 128.33 ± 11.59 mg Fe (II)/g DW (roselle calyx extract). On the other hand, TEAC values were in the range of 15.26 ± 2.83 µg Trolox/g DW (roselle calyx extract) to 364.27 ± 7.14 µg Trolox/g DW (blue butterfly pea flower extract). A significant moderate positive correlation was observed between TPC and DPPH (r = 0.562) as well as TPC and FRAP (r = 0.686).

This study was the first to compare the total phenolic content and antioxidant activities in coloured plants. Findings derived from this study can be extended to the formulation of natural food colourants and nutraceuticals.