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Statistical Analysis of Sample at Three Stages
of Maturity on Some Characteristics of Carambola Fruit (
Averrhoa
Carambola L
) before Enzymatic and Micro Filtration Processing
Lilis Sukeksi, Che Rosmani Che Hasan, Nik Meriam Nik Sulaiman, Mohamed Kheireddine Aroua, Abdul Ghani L.Y. and Zuraini Ahamad Sidik
Department of Chemical Engineering, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia
Email : lilissukeksi79@yahoo.com
Abstract
The mature stage of the fruit at harvest is of fundamental importance, because the fruit varies widely in its composition during maturation. A methodology for the evaluation of a reliability of fruits sample at three stages of maturity on the physical and chemical characteristics of carambola fruit (Averhoa Carambola L.) before enzymatic and micro filtration processing is presented. This approach is a valuable alternative to the evaluation of adequate statistical analysis information using the Statistical Quality Control (SQC).
The results of the analyses conducted during the research confirm that the dimension, weight, pH and soluble solid were different at three stages of maturity. The pH of the fruit juice increased with the advance in maturity, whereas ripe fruits were significantly less acidic than green unripe and half-ripe fruits. The entire reliability graph appointed all the data falls within the common or normal range of variation and exhibit a normal distribution.
Keywords : fruit, maturity, characteristics, reliability, sample
1. Introduction
Fruits and vegetables are good dietary sources of natural antioxidants for dietary prevention of degenerative diseases. The main contribution to the antioxidant capacity of a fruit or vegetable is likely to come from a variety of phytochemicals other than vitamin C. Fruits and vegetables contain many antioxidants such as phenolics, thiols, carotenoids and tocopherols. Therefore, increased consumption of fruits and vegetables has been recommended. To avoid loss of nutrition value, it is usually encouraged to consume fruits and vegetables fresh. However, sometimes for the purpose of transportation, extension of shelf life, etc., they are also pressed into juices.
The carambola is believed to have originated in Ceylon and the Moluccas but it has been cultivated in Southeast Asia and Malaysia for many centuries. It is a small tree with attractive foliage, produces large quantities of fruit and is recommended for the home orchard. The fruit has five corners and is described as star-shaped, and commonly called the Star Fruit. Very crisp and juicy and a refreshing taste, may be green to orange depending on the variety and maturity. It is usually consumed fresh or made into fruit juices or juice drinks.
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between sugar content and fruit quality. The mature stage of the fruit at harvest is of fundamental importance, because sugar content does not increase after this moment. Therefore, if the fruit is not sufficiently mature when harvested, it will not reach an optimum level of ripening, the taste very sour and if it is too ripe, its storage life will decrease. The capability of the fruit for storage and to supply fruits full ripe to the market at longer periods without damaging is difficult. Carambola utilization, whether in the producer country or for export to premium markets, it’s always been limited by the perishable nature of the fruit. Besides the chemical and composition depends on the cultivar, environmental conditions and also on the stage of maturity of the fruit.
To reduce the storage and to achieve longer storage, fruit juices are usually concentrated by multy-stage vacuum evaporation. This process results in a loss of fresh juice flavors, color degradation and a cooked taste due to the thermal effects. Since consumers generally prefer the flavor, aroma, appearance and mouth feel of freshly squeezed juices, scientist and processors have tried to develop new techniques for retaining such characteristics of juice. Many efforts have been devoted to develop improved methods such as freeze concentration, sublimation concentration and membranes for juice processing.
The quality assurance in a processing must be built on the knowledge of the analytical method performance, including the whole procedure between the sample and the final result. When the target of analysis has a constant size and heterogeneity, this evaluation can be extended to the sampling procedure. However, this is often not the case, and in those cases, the sample should be obtained by a conventional procedure function of the expected average heterogeneity of the sample item. Nevertheless, the chosen sampling procedure and the selected quality assurance scheme must always have in mind the purpose of analysis.
In traditional or premium market the stage maturity of carambola always in three stages of maturity, which is green, yellow and orange and no cultivar information that could be become different in properties. To analyze antioxidant, vitamin c or total sugar in the carambola, the sample has to come from the same cultivar to result the same characteristics. But to get the same cultivar the sample has to come from the one farming. The present study was only preliminary study to analyze some characteristics of carambola by statistical analysis method to determine the differences of the three stages of maturity before enzymatic and micro filtration processing. The purpose of this work was to evaluation the reliability characteristics of the carambolas from the market at three stages maturity.
2. Materials and Methods
Carambola fruits
Carambola (Averrhoa Carambola L.) fruits of an unidentified variety were collected fresh from the local market in Kuala Lumpur. The fruits selected were free from physical damage and close in range of dimension and classified into three apparent maturities according to their firmness and skin color; (1) Green mature – firm texture and skin 100% green; (2) Half-ripe – firm texture and skin yellowish green, and (3) Ripe – soft texture and skin 100% yellow to orange.
Physical Analysis
Twenty-five fruits of each maturity group are individually analyzed for physical characteristics. Fruits were weighed in the air on a balance of accuracy of 0.01 g. Length and diameters of the fruit were measured with a vernier caliper and volume by a liquid displacement method. The measurement of length was made in the polar axis of fruit, i.e. between apex and stem. The maximum width of the fruit, measured in the direction perpendicular to the polar axis, was denominated as diameter.
Chemical Analysis
The carambolas were cut with a stainless steel knife to remove the edible portion and chopped into small pieces. The fruits were then blended using Pensonic Juice Extractor. The soluble solids content was carried out using an Atago Hand Refractometer and the result was expressed in degree Brix at 20°C. The pH was measured at 20°C, using a Cyber Scan 510 pH-meter.
Statistical Analysis
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variability such as the standard deviation and range of the distribution of data. A control chart is a graph that shows whether a sample of data falls within the common or normal range of variation and that can be measured for continuous scale, such as height, weight, volume, or width and etc. A control chart has upper and lower control limits that separate common from assignable cause of
variation. The upper and lower control limits on a control chart are usually set at ± 3 standard
deviations from the mean. If we assume that the data exhibit a normal distribution, these control limits will capture 99.74 percent of the normal variation [8], [9].
3. Results and Discussion
Table 1 Dimension and weight of the carambola fruits
Apparent maturity Average all the
Parameter
Green Half-ripe Ripe Fruit
Length (cm) 11.68 ± 0.43 11.48 ± 0.40 11.28 ± 0.47 11.48 ± 0.43
Diameter (cm) 7.60 ± 0.26 7.30 ± 0.32 7.42 ± 0.50 7.44 ± 0.36
Weight (g) 160.31 ± 11.75 155.13 ± 13.42 152.48 ± 16.46 155.97 ± 13.88
During ripening, a fruit passes through a series of changes in color, texture and flavor indicating that compositional changes are taking place. The dimensions of the carambola fruits and its components are presented in Table 1. The length of the fruit varied from 11.68 cm for green mature to 11.48 cm for half ripe and 11.28 cm for the fully ripe fruit. The diameter of the green fruits is 7.60 cm, 7.30 cm for half ripe and 7.42 cm for the fully ripe fruit respectively. Physical properties of all stage carambola fruits showed no statistical differences in length and diameter. Their standard deviations are 0.43, 0.40 and 0.47 for length and 0.26, 0.32 and 0.50 for diameter respectively from the green to ripe fruit. A small standard deviation indicates that they are clustered closely around the mean. The length and diameter data on the fruit at all stages of maturity relate to its oblong shape. In a study on physical and chemical composition of carambola fruit at three stages of maturity to the cultivar Golden Star reported that the length of the fruit varied from 6.75 for green mature to 7.92 for the fully ripe fruit [4].
The diameter of the ripe fruits was also larger (5.24 cm) than that of the green mature (4.69 cm). They also reported average fruit weight of 57.32 g, which is within the range of 152.48 g for fully ripe fruit and 160.31 g for green mature. However, there was a great variation in the weights of individual fruits at different stages of ripeness. The weight of the green mature fruit was found to be significantly different than those of half-ripe and ripe fruits. These values decrease from unripe, through half-ripe to full ripe fruit. Their standard deviations are 11.75, 13.42 and 16.46. The large standard deviation indicates that the data points are far from the mean. These values from length, diameter and weight, appointed that the carambola fruits have a different cultivar with the cultivar Golden Star.
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Each parameter is in between UCL and LCL.
(c)
Figure 1 Reliability graph of dimension and weight of the carambola fruits
Table 2 Physical-chemical parameters of the carambola juice
Apparent maturity Average all the
Parameter half-ripe and ripe fruit juices that are 72.12 ml, 67.56 ml and 77.40 ml and the standard deviation indicates that the data points are far from the mean; their standard deviations are 7.44, 8.66 and 14.05 respectively from green to ripe fruit. However, from the graph of reliability all the data falls within the common or normal range of variation and exhibit a normal distribution.
The pH of the fruit juice increased with the advance in maturity, being 3.15 for green mature, 3.39 for half-ripe and 3.59 for ripe fruit juices. These relatively lower pH values characterized the acidic flavor of the fruit juices. The pH value increased from the unripe fruit to full ripe fruit has been reported [7], [6], [4]. The standard deviations from the green fruit are 0.13, 0.1, and 0.22 to the ripe fruit respectively that indicate the data points are small from the mean and the graph of the reliability falls within the common range and exhibit a normal distribution.
5 chemical properties during pomegranate fruit maturation and Lucia et al., [7] in physicochemical characteristics of Bilimbi shows the same with the present investigation that no statistical differences in pH and soluble solid.
(a) Reliability graph for volume of carambola juice
(b) Reliability graph for pH of carambola juice
(c) Reliability graph for soluble solid of carambola juice
(d) Reliability graph for volume/100g FW of carambola
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4. Conclusions
The current study appointed that the dimension of Carambola fruit such as length and diameter slightly change from the green mature stage to ripe fruits. The weight fruits significantly decrease during maturation, which is 160.31 g for green mature stages to 155.13 g for half ripe fruit and 152.48 g for full ripe fruits. The pH and soluble solid appointed slightly different but no statistical differences between all the stages of maturation.
The knowledge of the exact qualitative and quantitative distribution of the sample for carambola fruits is of capital importance for the evaluation quality of fruits before enzymatic and micro filtration processing. The accurate analysis of those components enables us to observe the changes in the production of carambola juice during the storage time and stages maturity of the fruit. To establish the slightly differences among the other parameter is also necessary to eliminate degree of ripeness, such as green mature because no statistical differences in quality between all stages of maturity are observed.
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