The effects of sodium chloride (NaCl) (3.5%) solution and polysaccharides, such as carboxymethyl cellulose (CMC) (0.1, 0.3 and 0.5%) and gum arabic (5, 10 and 15%), on the physicochemical properties, antioxidant capacity and sensory characteristics of bitter gourd juice were investigated. An increase in the concentration of CMC and gum arabic significantly was observed to increase the lightness (L value) and the viscosity (mPas) of bitter gourd juice at all levels. Increased concentrations of gum arabic significantly increased the total soluble solids. The bitter gourd fruit treated with NaCl solution produced the highest lightness (L value) and scavenging activity of free radical 2,2-diphenyl-1-picrylhydrazyl of bitter gourd juice. Increased concentration of gum arabic up to 15% significantly increased the total phenolic content. The addition of 5% gum arabic effectively reduced the bitterness of the bitter gourd juice. Viscosity of the juice resulted in negative correlation for bitterness.
The high pectin content in papaya (Carica papaya) causes the juice extraction to be difficult and results in a low yield. This study aims to determine the effect of acidified blanching water and pectinase enzyme pretreatments on the yield, physicochemical properties, and antioxidant activities of the papaya juice. For acidified blanching treatment, papaya cubes (3 cm3) were blanched in water containing 0%, 0.5%, 1.5%, and 2.5% w/v citric acid at 95℃ for 2 min. For enzyme treatment, a pectinase enzyme (10, 20, and 30 ppm) was added to the homogenous papaya puree and incubated at 45℃ (200 rpm) for 60 min. The enzyme reaction was stopped by pasteurization at 74℃ for 2 min. The puree was filtered, and the juice was pasteurized at 74℃ for 7 min. All pretreated papaya juice were analyzed for physicochemical properties (color, clarity, viscosity, pH, total soluble solids [TSSs], total carotenoid content, total phenolic content [TPC], and total flavonoid content [TFC]), and antioxidant activities (2,2‐diphenyl‐1‐picrylhydrazyl [DPPH] and ferric reducing antioxidant power [FRAP] assay). Both pretreatments improved the clarity of papaya juice, and was significantly greater after pretreatment with pectinase enzyme. The TPC and antioxidant activities of papaya juice were conserved and maintained by acidified blanching at 1.5% (w/v) citric acid. Increased concentrations of pectinase enzyme significantly reduced the TPC and total carotenoid content. Pretreatment with pectinase enzyme up to 20 ppm does not significantly reduce the TFC and antioxidant activities. Acidified blanching and pectinase enzyme pretreatments have an impact on extraction of papaya fruit juice while retaining the nutritional composition of the juice.
Practical Application
Papaya (Carica papaya) is a fruit with great nutritional values but is highly perishable and prone to postharvest loss. Juice has become a more cost‐effective and convenient option for preserving the fruit. However, since papaya is a pectin‐rich fruit, the extraction of juice using mechanical pressing is difficult due to the bonding of juice to the pulp in the form of a jellied mass, which results in juice with low yield. Using acidified blanching and pectinase enzyme to clarify the juice not only increases the yield but also retains the nutrient composition of the juice.
This study was conducted to evaluate consumer profiling of pineapple at five maturity stages using check-all-that-apply (CATA) method and to determine the influence of post-harvest physiological changes on the physical and chemical properties of the pineapple. Nineteen CATA terms describing sensory attributes of pineapples at five maturity stages were generated. Seventy-five consumers were involved in describing the changes in the organoleptic properties of pineapple using CATA questions. The relationship between physicochemical properties and sensory description of pineapples was analyzed using correspondence analysis (CA). The total variance of 97.7% and 92.2% obtained in the CA plot of the physical and chemical properties with the consumer profiling data suggests that consumers have effectively described the pineapple harvested at five maturity stages. Changes in physical and chemical compositions in pineapple upon maturation result in the development of pineapple's desirable organoleptic characteristics, characterized as fresh, attractive, and bright yellowish, with a soft, fibrous, and juicy texture, a sweet odor and pineapple aroma as well as sweet taste. Index 3 pineapple has been described as pale, hard, and crunchy in texture at the early stage of maturity and has a sour taste. The characteristic was transformed to bright yellow, soft, fibrous, and juicy texture after maturation, (25% ripeness onwards), as well as the production of sweet taste and aroma of pineapple. Instrument analysis of yellowness (b value) and carotenoid has strongly influenced the sensory attributes of brightness, freshness, and attractiveness of the pineapple. Changes in total soluble solids (TSS) and a ratio of TSS to total acids (TA) contributes to the development of aromatic compound which increases the appealing quality of the pineapple. Pineapple sensory characteristics, physical properties, and chemical compositions were significantly affected by post-harvest physiology.Practical Application: Sensory and instrumental methods were used to construct the properties of pineapple at different stages of post-harvest physiology. This article demonstrates that the Check-all-that-apply (CATA) analysis provides adequate sensory profiling information based on customer perceptions in
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