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Aim: To investigate the preservative efficiency of Ocimum gratissimum or its extracts on yoghurt. Study Design: Ten yoghurt samples were prepared, furthermore, nine (9) samples were treated with scent leaf in different forms at different concentrations. Place and Duration of Study: Department of Food Science and Technology, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria, between September 2015 and June 2016. Methodology: Yoghurt was prepared from instant filled milk while Direct Vat Inoculum (DVI) was used as the starter culture. Proximate and phytochemical analyses were carried out following standard procedures. Sensory evaluation was carried out using a 15-man panelist with a seven point hedonic scales and results were statistically analyzed using IBM® SPSS 21.0, at 0.05 probability level. pH and microbial analysis were conducted while bacterial characterization involved biochemical tests and isolation of probable microorganisms employed morphological and structural characteristics. Results: Result for proximate analysis indicated differences in the nutritional composition of the raw milk and yoghurt (control). Moisture content increased considerably from 10.00% to 69.75%, while a reduction in protein content was reported (8.7% - 4.95%). The lipid content classified the produced yoghurt as a low-fat yoghurt, and expectedly, the carbohydrate content reduced from 58.20% - 22.30%. Phytochemical screening of the different forms of scent leaf indicated the presence of alkaloids, flavonoids, saponins, cardiac glycosides, and steroids, in different concentrations. Sensory scores showed that the panelists preferred yoghurt formulated with 3 mL of squeezed scent leaf extract. pH values decreased with storage period, while microbial load ranged between 0.5× 104 – 2.0 × 104, where Klebsiella spp., Streptococcus spp., E. coli, Bacillus, S. aureus, Pseudomonas spp., Enterobacter, and Proteus spp. were isolated. Conclusion: The yoghurt samples formulated with squeezed scent leaf extracts had the best organoleptic acceptance, while the sample treated with 3 mL had the lowest microbial load, hence, it can be inferred that the squeezed scent leaf extracts had the best preservative effect.

Aims: To investigate the physicochemical, sensory and microbial qualities of ice cream stabilized with hydrocolloids from Achi (Brachystegia eurycoma) and Ofor (Detarium microcarpum. Study Design: A 4×5 split-plot in completely randomized design. Place and Duration of Study: Department of Food Science and Technology, Faculty of Agriculture, University of Nigeria, Nsukka, Enugu State Nigeria between August 2018 and July 2019. Methodology: Raw seeds of Achi (Brachystegia eurycoma) and Ofor (Detarium microcarpum) were purchased from Ekeonunwa market, Owerri, Imo State, Nigeria and processed into flours. Hydrocolloids from flours of Achi and Ofor were defatted with n-hexane (50 g/250 ml at 26±2°C) dispersed in distilled water (10 g/250 ml), centrifuged (1250 rpm/30 mins and 1500 rpm/30 mins for achi and ofor respectively). The supernatants obtained were dissolved in isopropanol, decanted dried in a hot air oven (60°C, 10 h), pulverised using a blender and stored in air –tight containers. Twenty (20) litres of ice cream samples were produced. Four (4) litres of the mix was measured out as control (i.e. plain ice cream without any stabilizer). Sixteen (16) additional ice cream mixes were produced in the same way by the addition of CMC, achi hydrocolloids, ofor hydrocolloids and a mixture of hydrocolloids from both achi and ofor as stabilizers, each at 0.1%, 0.2%, 0.3%, 0.4% concentrations. The physicochemical, sensory and microbial properties of the ice cream samples formulated were carried out. Results: The outcome of physicochemical analysis revealed that viscosity (31.65 ± 0.17 cP – 82.50 ± 0.00 cP), overrun (19.30 ± 0.00% - 98.73 ± 0.00%), total solids (24.36 ± 0.33% - 54.00 ± 1.55%) and melting resistance (36.50 ± 0.58% -  92.50 ± 0.58%) were significantly (P < 0.05) affected by the type of stabilizers as well as their concentrations. The total titratable acidity (0.02 ± 0.00% -  0.02 ± 0.00%) and pH (6.74 ± 0.00 - 7.05 ± 0.05) of the ice cream samples showed no appreciable significant (P > 0.05) difference. The overall acceptability (5.80 ± 1.99 - 7.65 ± 1.00), aftertaste (5.45 ± 2.28 – 7.20 ± 0.89), mouthfeel (5.85 ± 1.79 - 7.25 ± 1.37) and homogeneity             (5.20 ± 1.96 - 7.60 ± 1.39) were significantly (P< 0.05) influenced as deduced from the sensory result. Conclusion: The incorporation of local stabilizers significantly improved the physicochemical, sensory and microbial qualities of ice cream produced. Hydrocolloid extracts of Detarium microcarpum (Ofor), plant-based natural stabilizer is a capable replacer of CMC in ice cream production because of its higher viscosity than other stabilizers and CMC, agreeable consistency, better consumer preference than other stabilizers, enhanced qualities – slow melting rate i.e. high melting resistance, commendable pseudo-plasticity, effectual overrun which will yield more profits for ice cream manufacturers, bring about a new variety of ice creams that are safe for consumption. Hydrocolloid extracts of Detarium microcarpum, at 0.3%, showed more desirable similar effects on the physicochemical, sensory and microbial qualities of ice cream samples formulated compared to CMC and could, therefore be recommended as a replacer of CMC in ice cream production.

Aims: To Investigate the Proximate, Physicochemical and Sensory attributes of Stirred Yoghurt Flavoured with African Star Apple Pulp (Chrysophyllum albidum). Study Design: Randomized Completely Block Design (RCBD). Place and Duration of Study: Department of Food Science and Technology, Faculty of Agriculture, University of Nigeria, Nsukka, Enugu State Nigeria between December 2018 and October 2019. Methodology: The materials, as well as the other ingredients for the preparation of the flavoured stirred yoghurt (African star apple, skimmed milk, sugar, and Starter culture (YoghurmetTM) were sourced from Ogige main market in Nsukka Local Government Area of Enugu State, Nigeria. The African star apples were sorted to separate the fresh and good fruits from insect-infected and mechanically damaged ones. The fruits were thoroughly washed with water to further eliminate adherent dirt so as to obtain sand-free fruits. Peeling of the fruits was done to remove the back. Each of the peeled fruits was cut into two in order to remove the seeds thereof. The pulps were carefully removed manually with knife and the pulps were blended using a blender after which pasteurization at 83°C for 3 minutes was carried out before being added to the processed yoghurt. Yoghurt flavoured with pasteurized African Star Apple pulp was produced by homogenizing, pasteurizing the milk product followed by cooling to inoculation temperature which is optimum for the starter culture (Yoghurmet). The inoculated milk was made to undergo fermentation after which the pasteurized African star apple pulp at different proportions was added to formulate five samples of stirred yoghurt.  The formulation ratios of yoghurt to African star apple pulp were as follows: 100:0, 90:10, 80:20, 70:30, 60:40, 50:50. The flavoured yoghurt samples were mixed, smoothened and packaged for cold storage. Results: The result of physicochemical analysis revealed that viscosity (2.65 ± 0.06 cP – 3.25 ± 0.06 cP), total solids (22.35 ± 0.06% - 30.20 ± 0.06%), total titratable acidity (0.36 ± 0.00% -   0.39 ± 0.01%) and pH (5.20 ± 0.00 - 5.40 ± 0.00) differed significantly (P < 0.05) as the control sample YC (100:0) was compared with the yoghurt samples flavoured with African star apple pulp. The proximate parameters -  Carbohydrate (11.20 ± 0.64% - 21.41 ± 0.10%), moisture content (71.53 ± 0.05% - 80.36 ± 1.17%) and ash content (1.30 ± 0.00% - 1.98 ± 0.03%) of the formulated yoghurt samples showed significant (P < 0.05) decrease as concentration of ASA pulp increased while crude protein (3.67 ± 0.01% -  4.92 ± 0.02%), fat (1.21 ± 0.02% - 2.72 ± 0.03%) and crude fibre (0.20 ± 0.00% - 1.40 ± 0.00%) showed significant (P < 0.05) increase with increasing concentration of ASA pulp. Among the formulated yoghurt samples, sample YP1 was the most preferred with respect to color (7.25 ± 0.91), taste (7.25 ± 1.07), aftertaste (7.00 ± 1.17), mouthfeel (6.95 ± 1.40), flavour (7.25 ± 0.64) and overall acceptability (7.30 ± 0.73). Conclusion: Although the control sample YC (100:0) had most preferred sensorial qualities, yoghurt samples flavoured with African Star Apple pulp would rival the “used-to plain yoghurt” with improved awareness, and usage lower than 20% of the ASA pulp in yoghurt samples would maintain the product’s acceptability among the variety-loving dairy consumers.

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