Ripeness Index Research Articles

Quantitative Classification and Prediction of Starkrimson Pear Maturity by Near-Infrared Spectroscopy

Scientific evaluation of pear maturity is important for commercial reasons. Near-infrared spectroscopy is a non-destructive method that could be used for rapid assessment of pear maturity. The aim of this study was to develop a reasonable and effective method for the assessment of Starkrimson pear maturity using near-infrared technology. Partial least squares regression and five classification methods were used for analysis of the data. Among the indices used with the competitive adaptive reweighting–partial least squares regression method for quantitation, the visual ripeness index had the best modeling effect (Rp2: 0.87; root mean square error of prediction: 0.39). The classification model constructed with the visual ripeness index and post-ripeness score gave a cross-validation neural network model with the best classification effect and the highest accuracy (classification accuracy: 88.7%). The results showed that combination of quality indices with near-infrared spectroscopy was effective for rapidly evaluating the maturity of Starkrimson pears.

Physicochemical properties of sweet limes (Citrus limetta) during storage at different temperatures

The loss of nutrients from sweet lime (Citrus limetta) by poor postharvest storage represents a significant problem today, damaging these fruits’ quality and market value. This study aimed to evaluate the physicochemical properties of sweet limes during storage at different temperatures (RT-21°C, 2°C, and 4°C). The limes were harvested at full physiological maturity. Water activity (Aw), pH, color index, total soluble solids, titratable acidity, and ripeness index were determined during 15 days of storage. In addition, antioxidant activity and phenolic content were determined. The results indicate that keeping the sweet lime at a temperature of 4°C is the most favorable condition for optimal conservation, as reflected by the reduction in Aw, titratable acidity, total soluble solids and ripeness index of the fruit. The values obtained indicate slower decomposition and conservation of freshness and flavor. In addition, it was found that at this temperature, the fruit’s antioxidant activity and phenolic content were significantly increased. In addition, total polyphenols were better preserved at 2°C compared to room temperature (RT) and 4°C. However, ABTS and DPPH levels remained constant at 4°C and 2°C throughout the study time and were higher than at RT.

Guava ripening and quality in response to pre-harvest boron spraying

The physiological process of guava fruit ripening is difficult to manage in orchards. Boron (B) is a nutritional element with a physiological effect on fruit ripening through its role in ascorbate metabolism. This study evaluated the effects of single boron pre-harvest spraying on fruit ripening and post-harvest. The treatments consisted of B-monoethanolamine (MEA) sprays (11% B) at concentrations of 0 (control), 1, 2, and 3ml L-1. Foliar sprays were applied on guava trees cv. Cortibel RG, at the physiological stage Biologische Bundesanstalt, Bundessortenamt, und Chemische Industrie (BBCH) 78 (fruits at 80% of final growth). The study used a randomized block design with five replicates. Fruits were harvested 5, 8, 15, and 17 days after B-MEA spraying. The nutritional content was assessed in the leaves and fruits. The fruits were analyzed for ascorbic acid content (AA), total sugars, reducing and non-reducing sugars, titratable acidity, soluble solids, ripeness index, total phenolic compounds, total carotenoids and total anthocyanins. Moreover, the fruit weight, length and diameter were measured and yield were assessed. Fruit firmness and mass loss were evaluated post-harvest. The data showed an increase in ascorbic acid content in the fruit in all treatments with B-MEA sprays. Spraying B-MEA 3 ml L-1, or 180.84 g ha-1, increased the earliness and standardization of ripening, which took place over a shorter period of time, maintaining firmness and reducing post-harvest fruit mass loss.

Improvement of the prediction of a visual apple ripeness index under seasonal variation by NIR spectral model correction

Apple ripeness assessment is essential to ensure its post-harvest commercial value, and the visible/near-infrared(NIR) spectral models that are effective in achieving this goal are prone to failure due to seasonal or instrumental factors. This study has proposed a visual ripeness index (VRPI) determined by parameters such as soluble solids, titratable acids, etc., which vary during the ripening period of the apple. The R and RMSE of the index prediction model based on the 2019 sample were 0.871 to 0.913 and 0.184 to 0.213 respectively. The model failed to predict the next two years of the sample, which was effectively addressed by model fusion and correction. For the 2020 and 2021 samples, the revised model improves R by 6.8% and 10.6% and reduces RMSE by 52.2% and 32.2% respectively. The results showed that the global model is adapted to the correction of the VRPI spectral prediction model under seasonal variation.

Monitoring the maturity of Ahmeur Bouamer Autochtonous variety and determining of the optimum harvest date

Morphological ampelography characteristics, technological, phenolic and tannic maturities were studied over four seasons (from 2009 to 2012) of Ahmeur Bouamer autochtonous Algerian variety. During the four harvests, Ahmeur Bouamer's cluster has showed a high quality of morphological parameters (weight, size, number of seeds/ berries per cluster).The weight was proportional to the size of the cluster which was moderately compact, thus avoiding the deformation and the bursting of the berries. As For the maturity index (MI), Ahmeur Bouamer grape recorded values ranging from 31.07 to 54.95 for the four seasons; values which would make it possible to consider that the harvest would be of excellent quality (when 30 <MI <50). As well as for total anthocyanin potential (TAP) exceeding 1000 mg / L and total polyphenol index (TPI) with values greater than 50, these values confirm that the cluster presents high level of maturity. The monitoring of the MI every week in the phase of ripening (september-october) for 2010 and 2011 have showed that the maximum ripeness index was reached on September 27th with highest level of maturity for both harvests, date that can be considered by the winemaker as optimal date of harvest.

Feasibility of Early Yield Prediction per Coffee Tree Based on Multispectral Aerial Imagery: Case of Arabica Coffee Crops in Cauca-Colombia

Crop yield is an important factor for evaluating production processes and determining the profitability of growing coffee. Frequently, the total number of coffee beans per area unit is estimated manually by physically counting the coffee cherries, the branches, or the flowers. However, estimating yield requires an investment in time and work, so it is not usual for small producers. This paper studies a non-intrusive and attainable alternative to predicting coffee crop yield through multispectral aerial images. The proposal is designed for small low-tech producers monitored by capturing aerial photos with a MapIR camera on an unmanned aerial vehicle. This research shows how to predict yields in the early stages of the coffee tree productive cycle, such as at flowering by using aerial imagery. Physical and spectral descriptors were evaluated as predictors for yield prediction models. The results showed correlations between the selected predictors and 370 yield samples of a Colombian Arabica coffee crop. The coffee tree volume, the Normalized Difference Vegetation Index (NDVI), and the Coffee Ripeness Index (CRI) showed the highest values with 71%, 55%, and 63%, respectively. Further, these predictors were used as the inputs for regression models to analyze their precision in predicting coffee crop yield. The validation stage concluded that Linear Regression and Stochastic Descending Gradient Regression were better models with determination coefficient values of 56% and 55%, respectively, which are promising for predicting yield.

Effect of gelatin–alginate coating containing anise ( Pimpinella anisum L.) essential oil on physicochemical and visual properties of zucchini ( Cucurbita pepo L.) fruit during storage

The present study investigates the possibility of extending the shelf life of zucchini fruit treated with gelatin–alginate (G–AL) coating containing different concentrations (0.85%, 1.7%, and 2.55% w/v) of anise essential oil (AEO) during room storage (RS) and cold storage (CS). Physical properties including weight loss (WL), tissue firmness, and volume changes (VC); chemical properties including pH, titratable acidity (TA), and total soluble solids (TSS), and ripeness index (RPI); and visual properties, such as color index, percentage of surface defects, and zucchini chilling injury index (CI) were measured on 0, 3, 5, 7, 9, and 14 days of storage. Finally, the parameters were modeled using the zero-order, first-order, and Weibull function kinetic models. The results showed that in all treatments, quality changes during RS was significantly (p < 0.05) faster than CS. G–AL coating without AEO (C1) was able to change WL, texture firmness, volume changes, TA, TSS, and percentage of surface defects, color changes and reduce CI by 14%, 18%, 19%, 55%, 7%, 43%, 37%, and 34% respectively. The addition of AEO to the coating at different concentrations increased its efficiency and significantly reduced the trend of quality changes compared with C1 in both RS and CS (p < 0.05). The zero-order, first-order, and Weibull kinetic models were able to predict quality parameters with R2 higher than 0.90. However, the first-order model with R2 higher than 0.98 showed the best performance. It can be concluded that G–AL coating containing AEO could be used as an active edible coating in the storage of zucchini fruit. Novelty Impact Statement Addition of AEO to the G-AL coating at different concentrations increased its efficiency and significantly reduced the trend of quality changes G-AL coating containing AEO could be used as an active edible coating in the storage of zucchini fruit The results showed that the coating treatment, especially with high concentrations of AEO, could significantly reduce the CI rate.

Study on qualitative impact damage of yellow peaches using the combined hyperspectral and physicochemical indicators method

Yellow peaches are soft and prone to impact damage, and the end-use and sales price of yellow peaches are directly affected by their damage degree. Hyperspectral technology has the advantages of fast, non-destructive, etc. It is feasible to directly detect the collision degree of fruit. However, the physicochemical indicators and storage time of fruit after bruise are different, which affect the robustness of the classification model. The geometric parameters are used to assess the damage degree of fruit, but the damage degree is not always positively correlated with geometric parameters. And the damaged fruit can directly lead to changing in its internal quality, and its physicochemical indexes are also affected, so, in order to quickly and accurately identify the impact damage degree of yellow peaches, a combined hyperspectral and physicochemical indicators method is proposed to classify and identify the different levels of impact damage of yellow peaches in this study. In the study process, firstly, the spectral data of samples is extracted and the physicochemical indexes of samples are determined. Then, the statistical analysis of each physicochemical index is performed and the models of them are established. Finally, the value of ripeness index (RPI) is used to characterize the impact damage degree of yellow peaches. The damaged yellow peaches are divided into three groups according to the value of RPI. The value of RPI of damaged yellow peaches greater than 2 is defined as lightly bruise, the value of RPI between 1.2 and 2 is defined as moderately bruise, and the value of RPI less than 1.2 is defined as severely bruise. The results show that the performance of extreme gradient boosting (XGBoost) model under the raw spectrum is best, and the correctness of the prediction set is 93.1%. In conclusion, this study shows that the combined hyperspectral and physicochemical indicators method is feasible to assess the impact damage degree of yellow peaches and it provides a new method to assess the mechanical damage of fruit.

Volume estimation models for avocado fruit.

Avocado (Persea americana Mill.) is an important horticultural crop and proved to be a very profitable commercial crop for both local consumption and export. The physical characteristics of fruits are an important factor to determine the quality of fruit produced. On the other hand, estimation of fruit volume is time-consuming and impractical under field conditions. Thus, this study was conducted to devise cultivar-specific and generalized allometric models to analytically and non-destructively determine avocado fruit volume of five wildly distributed avocado cultivars. A significant relationship (P ≤ 0.01) was found between fruit diameter, length, and volume of each cultivar. Our best models (VM2 -for cultivar specific, and VM7-generalized model) has passed all the rigorous cross-validation and performance statistics tests and explained 94%, 92%, 87%, 93%, 94% and 93% of the variations in fruit volume of Ettinger, Fuerte, Hass, Nabal, Reed, and Multiple cultivars, respectively. Our finding revealed that in situations where measurements of volume would be inconvenient, or time-consuming, a reliable volume and yield estimation can be obtained using site- and cultivar-specific allometric equations. Allometric models could also play a significant role in improving data availability on avocado fruit physical appearance which is critical to assess the quality and taste of fresh products influencing the purchase decision of customers. Moreover, such information can also be used as a ripeness index to predict optimum harvest time important for planned marketing. More importantly, the models might assist horticulturists, agronomists, and physiologists to conduct further study on avocado production and productivity through agroforestry landuse system across Ethiopia.

Anti-Inflammatory and Antioxidant Activity of Hydroxytyrosol and 3,4-Dihydroxyphenyglycol Purified from Table Olive Effluents.

New liquid effluents based on the use of acetic acid in the table olive industry make it easier to extract bioactive compounds to be used for food, cosmetic, and pharmaceutical purposes. The use of water acidified with acetic acid or in brine with or without acetic acid for storing the table olive enhances the extraction of two more active phenolic compounds: hydroxytyrosol (HT) and 3,4-dihydroxyphenylglycol (DHPG). This work has two aims: (1) measure the solubilization of phenolics controlled for two years using more than thirty olive varieties with different ripeness index as a potential source of HT and DHPG, and (2) evaluate the anti-inflammatory activity of the purified phenolics. The effluents with a higher concentration of phenolics were used for the extraction of HT and DHPG in order to evaluate its antioxidant and anti-inflammatory activity in vitro by the determination of pro-inflammatory cytokines such as Human Tumor Necrosis Factor-α (TNF), Interleukin-6 (IL-6), and Interleukin-1β (Il-1β). The anti-inflammatory activity of these phenolic extracts was demonstrated by studying the expression of cytokines by qPCR and the levels of these proteins by enzyme-linked immunosorbent assay (ELISA).

A Novel Vegetation Index for Coffee Ripeness Monitoring Using Aerial Imagery

Coffee ripeness monitoring is a key indicator for defining the moment of starting the harvest, especially because the coffee quality is related to the fruit ripeness degree. The most used method to define the start of harvesting is by visual inspection, which is time-consuming, labor-intensive, and does not provide information on the entire area. There is a lack of new techniques or alternative methodologies to provide faster measurements that can support harvest planning. Based on that, this study aimed at developing a vegetation index (VI) for coffee ripeness monitoring using aerial imagery. For this, an experiment was set up in five arabica coffee fields in Minas Gerais State, Brazil. During the coffee ripeness stage, four flights were carried out to acquire spectral information on the crop canopy using two quadcopters, one equipped with a five-band multispectral camera and another with an RGB (Red, Green, Blue) camera. Prior to the flights, manual counts of the percentage of unripe fruits were carried out using irregular sampling grids on each day for validation purposes. After image acquisition, the coffee ripeness index (CRI) and other five VIs were obtained. The CRI was developed combining reflectance from the red band and from a ground-based red target placed on the study area. The effectiveness of the CRI was compared under different analyses with traditional VIs. The CRI showed a higher sensitivity to discriminate coffee plants ready for harvest from not-ready for harvest in all coffee fields. Furthermore, the highest R2 and lowest RMSE values for estimating the coffee ripeness were also presented by the CRI (R2: 0.70; 12.42%), whereas the other VIs showed R2 and RMSE values ranging from 0.22 to 0.67 and from 13.28 to 16.50, respectively. Finally, the study demonstrated that the time-consuming fieldwork can be replaced by the methodology based on VIs.

Spatial distribution of Crimean agroecological resources as a factor of variability of the main and secondary metabolites of grapes

The work is aimed at identifying the relationship between agroecological conditions and the formation of carbohydrate-acid and phenolic grape complexes. The agro-climatic parameters of 14 cv. ‘Cabernet Sauvignon’ industrial vineyards located in five wine-growing regions of Crimea have been determined using the methods of geoinformation and mathematical modeling. According to the similarity of 9 agro-climatic characteristics, the vineyards are united into 6 clusters, significantly different from each other. The dispersion of the main and secondary metabolites of grapes, as well as technological indicators based on them in the harvest from the selected clusters, has been established. According to the combined mass concentration of anthocyanins in berries, potential amount of extractable anthocyanins, anthocyanin extractability, monophenolmonooxygenase activity, glucoacidimetric index and grape ripeness index the selected vineyard clusters are discriminated with Wilks L. = 0.09 at α&lt;0.00001. Sugar content, active acidity index, glucoacidimetric index, and grape ripeness index were found to correlate inversely with the amount of precipitation during the growing season; anthocyanin extractability correlates directly with the Huglin and Winkler indices; monophenolmonooxygenase activity with the sum of active temperatures above 10 °C, Huglin index, total precipitation per year and growing season.

Optimal Maize Ripeness by Application of Dynamic Ripening and Analysis (DRA) System

The superiority of the dynamic ripening and analysis (DRA) system based on a filter for all directions of use compared to the currently valid ripening system with the usage-specific ripening figures separated into silage and grain maize in Germany is demonstrated in a system-biological way. The silage maize ripeness index (SRI) as the sole indicator for the fixation of the harvest time, the evidence of biotic and abiotic plant stress as well as the selection of environmentally and ripeness-stable maize varieties for all directions of use is multifunctional direction and filter. The grower can make crop decisions in the near-harvest period for planning the processes and carrying out the harvest to be optimized. The reference ripeness point (SRI of 2.8) enables the full exploitation of the phenotypic performance and resistance potential in maize cultivation by standardizing the ecophysiological optimal maize ripeness of genotype and phenotype and, in the long term, through the risk assessment of climatic changes. The social acceptance of maize cultivation can be significantly increased through the better economic and ecological aspects of the DRA system.

Influence of the Period of Peach Tree Chemical Thinning on Fruit Quality

The need to decrease production costs along with the lack of man power in the countryside has asked for cultural practices which lead to these factors, such as thinning. Thus, chemical thinning has been studied as an alternative to fruit manual thinning. Therefore, this study aimed at evaluating the quality of peach tree fruits after chemical thinning with metamitron at different time periods in the south of Brazil. The experiment was carried out in a commercial peach tree orchard with cultivars &amp;lsquo;Maciel&amp;rsquo; in Morro Redondo, Rio Grande do Sul state, Brazil, from 2015 to 2016. Treatments consisted in the application of metamitron (doses of 200 mg L-1) on the 20th, 30th, 40th, 50th and 60th day after full bloom (DAFB) and manual thinning on the 40th DAFB. Epidermis color, pulp firmness, ripeness index, soluble solids, titratable acidity, juice pH, total phenolic compounds and antioxidant activity were evaluated. The application of metamitron in peach tree thinning did not affect peach color. Changes in the other variables related to the quality of fruits depended on the application period of metamitron in the thinning process and between crops.

Effect of Ripening Degree of Argane Fruit on the Phenolic Composition and Antioxidant Activity of the fruit Pulp, Kernel and Oil

The quality of the vegetal oil depends to the quality of the fruit used during the extraction. Ripening of the fruit is one of the most important processes associated with metabolic changes in the fruit. These changes include variations in the fatty acid profile, fluctuations in the level of phenolic compounds. In the present study, we investigated the effect of ripening on the characteristics of Argane fruits including the variation of total phenol and flavonoid present in the pulp of the fruit, the kernel and the oil as well as their antioxidant potential. The rate of total phenol and flavonoid increases upon ripeness process in fruit parts and its oil; however, it decreases again in latest stages of ripeness. When compared to kernel extract and fruit pulp, oil extract with a ripeness index of 2.07 displays the highest inhibition of 2.2-diphenyl-1-picrylhydrazyl (DPPH). Moreover, it was revealed that the oil and kernel extract gave higher reducing power measured with the FRAP assay, It increases along the ripping process starting from ripeness index (RI) = 2.34 till 3.17.These results can be considered for a better use of fruit pulp press-cakes and oil as nutraceuticals or cosmetics. The study also helps to determine the best harvesting time in order to get a oil a high quality rich in phenolic compounds, and a large antioxidant potential which seems to be at ripeness index higher than 2.07 and lower than 3.07

PA and DA meter – providers of the new ripeness index?

New ripening instrumentation like the PA analyser and the DA meter offer non-invasive tools based on degradation of chlorophyll in the fruit peel; their values were compared with the Streif index measured by an ART system, as traditional ripeness viz., picking tool using 5-year-old 'Braeburn Hillwell' at Klein-Altendorf in autumn 2015, when environmental weather pattern delayed harvest by ca. 3 weeks. Treatments included two reflective mulches and two biostimulants with an untreated control. The study showed that: 1) DA meter values (IAD) gave consistent results for the four treatments at the six measuring dates before harvest; 2) DA meter values (IAD) highly correlated with r=0.84-0.94 with Streif indices (ART system); 3) when 'Braeburn' stopped ripening at Streif=0.18 (harvest window for Streif 0.25-0.14 and for starch 3-5), DA meter values still continued to decrease; 4) fruit with reflective mulch (Extenday) appeared earlier ripe with the DA meter but later ripe with the ART system; 5) if we start to manipulate ripening e.g., by chemicals (phosphates, biostimulants, reflective mulches, 1-MCP), Streif values may reflect those changes in ripening, whereas DA meter values (IAD) still continue to decline at the same rate, unless the treatment has a direct chlorophyll effect, where DA values may be tricky to use.

Olive fruit detachment force against pulling and torsional stress

Olive harvesting often requires high hand labour, considering that workers, with long poles or hand held devices, aid trunk shaker due to low harvesting efficiency. Currently, fruit detachment force (FDF) and fruit fresh weight were used to predict harvesting efficiency, although during harvesting process, fruit is subjected to bending and twisting movement besides pulling forces simulated by FDF measurements. For these reasons, the aim of the present study was to determine FDF evolution under different stalk twisting angles. In order to provide more information about mechanical behaviour of olive stalk, a trial was carried out during ripening process on four olive (Olea europaea L.) cultivars: Frantoio, Arbequina, Leccino and Maurino. FDF under traction force was measured after applying different stalk twisting angles (0°, 90°, 180°, 270°, 360°, 540°, 720º). FDF was considered to be 0 when fruit was detached from the bearing branch during the twisting process. Fruit weight, firmness, ripeness index and oil content were also measured to determine the optimal period for olive harvesting and olive ripening stage at each sampling date. FDF was significantly reduced, usually over 180º, when stalk was rotated before applying the pull force to measure FDF, keeping differences along fruit ripening process. Moreover, stalk twisting was an important variable for olive detachment, considering that fruits detached without pulling forces varied between 10.7 and 58.8% of the total fruits according with the different sampling dates. For these reasons, present and future harvesting systems, should take advantage of stalk susceptibility against torsion or bending strain to increase harvesting efficiency.

Effect of Deficit Irrigation Regimes on Yield and Fruit Quality of Olive Trees (cv. Memecik) on the Aegean Coast of Turkey

AbstractIn this study, six different irrigation treatments were applied to an olive orchard using the drip irrigation method. Five of these were arranged according to 25% (S0.25), 50% (S0.50), 75% (S0.75), 100% (S1.00) and 125% (S1.25) of the evaporation in 5 days of a class ‘A’ evaporation pan, and one control (SC) was arranged so as to bring the reducing moisture at a soil depth of 0–90 cm to field capacity. Yield values were not affected by the irrigation treatment (p &gt; 0.05). In contrast, 100‐fruit weight, pulp ratio, hardness moisture, oil, reducing sugar content and bitterness were affected by irrigation (p &lt; 0.05). Generally, an increase in the amount of irrigation water given in the study was accompanied by a fall in ripeness index values, a rise in moisture content, and a reduction in the oil content of fruit. The highest content of reducing sugar was obtained from S0.25, generally being lower with increase in the water applied. The findings show that application of 25% of the evaporation of a class ‘A’ evaporation pan (treatment S0.25) can be recommended for cv. Memecik. Application of this recommendation can achieve a 72% saving in water and make a significant contribution to the conservation of limited water resources. Copyright © 2017 John Wiley &amp; Sons, Ltd.

Effect of deficit irrigation on the postharvest of pear variety Triunfo de Viena (Pyrus communis L.) in Sesquile (Cundinamarca, Colombia)

A technique settled to optimize the use of water resources is known as Controlled Deficient Irrigation (CDI), for which this experiment was carried out to determine the effect of a three water laminae: 100 (T1), 25 (T2) and 0% (T3) crop's evapotranspiration (ETc) on the rapid growth phase of the pear fruit variety Triunfo de Viena.The fruit quality (fresh weight variation, osmotic potential, color, acidity, soluble solids, CO2 emission, dry matter, volume, firmness, ripeness index and moisture content) was evaluated over a two-month storage period. The first quality measurement was taken 2 days after harvest (DAH 8), with significant differences between treatments according to the Duncan test (P≤0.05):the largest fruit size was achieved with 100% ETc, (its diameter and volume were 7.70 cm and 217.5 cm3, respectively.), the firmness was higher in the treatment without water (T3), with a value of 8.02 N; however, during the rest of the storage time, there were no significant differences, showing water restriction during the rapid growth phase of the fruit provided 100% water savings without compromising quality in terms of fresh weight, total titratable acidity, color index, total soluble solids and moisture content.

Comprehensive ripeness-index for prediction of ripening level in mangoes by multivariate modelling of ripening behaviour

Abstract Prediction of ripeness level in climacteric fruits is essential for post-harvest handling. An index capable of predicting ripening level with minimum inputs would be highly beneficial to the handlers, processors and researchers in fruit industry. A study was conducted with Indian mango cultivars to develop a ripeness index and associated model. Changes in physicochemical, colour and textural properties were measured throughout the ripening period and the period was classified into five stages (unripe, early ripe, partially ripe, ripe and over ripe). Multivariate regression techniques like partial least square regression, principal component regression and multi linear regression were compared and evaluated for its prediction. Multi linear regression model with 12 parameters was found more suitable in ripening prediction. Scientific variable reduction method was adopted to simplify the developed model. Better prediction was achieved with either 2 or 3 variables (total soluble solids, colour and acidity). Cross validation was done to increase the robustness and it was found that proposed ripening index was more effective in prediction of ripening stages. Three-variable model would be suitable for commercial applications where reasonable accuracies are sufficient. However, 12-variable model can be used to obtain more precise results in research and development applications.