The effects of inlet temperatures of 140, 160, 180, 200 and 220ºC and maltodextrin (DE10-12) concentrations at 10, 20, 30, 40 and 50% (w/v) on the total phenolic content (TPC) and colour profile of spray dried Sapodilla powders were studied. The colour profiles and TPC of the sapodilla powder produced were measured using a Hunter Laboratory Calorimeter (L*, a* and b*) and Folin-Ciocalteu method, respectively. TPC of powders were significantly affected by the inlet temperature. However, an increase in the concentration of maltodextrin from 20 to 50% (w/v) did not significantly affect the adjusted TPC. A slight decreased in adjusted TPC when maltodextrin concentration increased from 10 to 20% (w/v). An increase in drying temperature did not significantly affect the a* (greenness to redness) and b* (blueness to yellowness) values. Spray dried Sapodilla powder slightly lost its L* (lightness) when inlet temperature increased from 200 to 220ºC. Higher concentrations of maltodextrin resulted in lower a* and b* values. L* increased significantly when the addition of maltodextrion increased from 10 to 20% (w/v). Spray dried Sapodilla powder added with 20 or 30% (w/v) maltodextrin and processed at 200ºC inlet temperature shows acceptable colour and TPC.
The physiochemical characteristics and microbiological study of spray-dried papaya powder
kept in aluminium laminated polyethylene (ALP) and polyethylene terephthalate (PET) at
accelerated storage (38 ± 2°C, 90% relative humidity (RH)) for 7 weeks were evaluated. The
final water activity (Aw) of the spray-dried papaya powder did not exceed 0.6 for both packaging
materials, which showed that the powder was shelf-stable. The overall adsorbed moisture of
spray-dried powder was significantly (p
Polyphenol oxidase (PPO) catalyzes the conversion of phenolic compounds into o-quinones which will lead to food browning. This phenomenon causes huge implications on food industries, as it degrades food quality over time. By combining both ammonium sulphate precipitation and gel filtration chromatography, PPO was partially purified up to 5.26-fold with 11.23% yield. The enzyme activity was 5120 EU/mL using 4-methylcatechol as substrate. Maximal PPO activity was found at 30oC, pH 5.0 for 4-methylcatechol and 40°C, pH 6.0 for catechol. The PPO showed a higher affinity towards 4-methylcatechol but higher thermal stability when reacting with catechol. The Km and Vmax values were 5.00 mM, 2000 EU/ml for 4-methylcatechol and 10.79 mM, 526.32 EU/ml for catechol. Energy for inactivation (Ea) obtained using 4-methylcatechol and catechol were 12.57 kJ/mol and 14.23 kJ/mol from respective substrates. Sodium disulfite was a better inhibitor where 79.17% of PPO inhibition was achieved. The isolation and characterization of round brinjal PPO serves as a guideline to predict the behavior of enzyme, leading to effective prevention of its browning during processing and storage.
‘Cempedak’ (Artocarpus integer L.) is an aromatic exotic tropical fruit that can be widely found in Malaysia during season. The pulp yield and several physicochemical properties of five varietes of ‘cempedak’ (CH27, CH28, CH29, CH30 and CH33) were determined. The latter included total soluble solids, titratable acidity, pH, color, organic acids, sugars and carotenoid contents. Sensory evaluation of the five ‘cempedak’ varieties was conducted using Hedonic test, in which the assessed attributes include color, taste, texture and overall acceptability. Results indicate that CH33 yield the highest percentage (35.8%) of edible portion (fruit pulp), while CH27 shows the highest tiratable acidity (0.52%). CH30 had the lowest L* value (52.41), and highest intensity of color in terms of redness (32.45) and yellowness (65.27) values. All ‘cempedak’ varieties were highest in sucrose content (12.28-20.02 g/100 gFW) compared to fructose (5.70-6.72 g/100 gFW) and glucose (4.94-5.52 g/100 gFW), while malic acid (0.430.70%) was the highest organic acid as compared to citric acid (0.24-0.60%) and succinic acid (0.20-0.33%). All the ‘cempedak’ varieties studied have high content of α-carotene (2.30-45.27 μg/100 gFW), followed by β-carotene (2.30-12.23 μg/100 gFW), with CH28 having the highest content. From the five varieties of ‘cempedak’ fruit examined, it was found that CH28 ranked the highest in terms of sensory properties, namely taste, texture and overall acceptability.