Effect of Altitude and Maturity Stages on Quality Attributes of Mandarin (Citrus reticulata Blanco)

Mandarin (Citrus reticulata Blanco) is a premier fruit crop which ranks in first position of the total fruit industry in Nepal. Studies were conducted to assess the maturity indices and quality parameters of mandarin at three altitudes i.e. 1300 m·asl, 1000 m·asl, and 700 m·asl with six maturity stages i.e. 11 Oct, 21 Oct, 31 Oct, 10 Nov, 20 Nov, and 30 Nov. The most important and reliable judging criteria of fruit maturity in mandarin i.e. fruit weight, external fruit colour, firmness, TSS, acidity, and TSS/Acid ratio, and vitamin C were experimented. The experiment results revealed that 1000 m·asl location was showed the highest fruit weight (104.9 g) and juice percentage (55.23) followed by 1300 m·asl altitude (99.5 g and 53.75% respectively) at 20th of November. The maturity advanced at lower altitude with 50 percent yellow orange rind colour, 10.98 TSS/acid ratio and 4 kg/cm2 firmness from 10th November at lower altitudes whereas it was appeared in 20th November at higher altitudes. The TSS/acid ratio was significantly higher (10.98) in the fruits of 700 m·asl as compared to 1300 m·asl (9.76) on 10th November, however, on 20th November 1300 m·asl showed the highest ratio (17.76). The fruit weight, juice content, TSS was found in increasing trends up to 20 November and then showed constant and decreasing trend. However, TA, firmness and vitamin C were showed in decreasing trends with time. The 1000 - 1300 m·asl was the best location for the mandarin production and 10-20 November was the best period for the mandarin harvesting for optimum maturity.

Quality and Shelf Life of Lisboa Lemon within Polystyrene Containers in Refrigerated Chamber

The aim of this research was to knowing if it would improve the shelf life of the lemons that were stored in hermetically polystyrene containers closed, as same that were placed in a refrigerated chamber with temperature of 10°C inside, high relative humidity (85%) and renovation of the air by action of the compressor of the chamber. Lemons cv “Lisboa” were cut directly from the orchard and washed with chlorinated water at 150 mg⋅L−1 sodium hypochlorite. The study variables were the color of the epicarp (shell) and the endocarp (pulp), polar and equatorial diameter, firmness of the pulp and total soluble solids concentration (°Brix) in the endocarp. The tone and purity of the yellow color of the shell (epicarp) and pulp or endocarp of the oranges increased significantly within polystyrene containers and, consequently, its quality was preserved and its shelf life was extended to more than 100 days without that they have symptoms of deterioration, by losses polar and equatorial diameter or decrease in total soluble solids. Inside closed containers polystyrene the temperature decreased to 2.0°C in the refrigerated chamber, so that the principle of thermal insulation polystyrene reaffirmed, and its functionality for packaging products, such as fruits, resolve some of their physiological problems themselves, to prolong its shelf life and improve its presentation.

Dielectric spectroscopy as a potential technique for prediction of kiwifruit quality indices during storage

Dielectric spectroscopy has been employed as a simple,low cost and a non-destructive way for prediction of some physicochemical indices of kiwifruit during storage.A parallel-plate capacitor was developed and supplied with sinusoidal voltage waves within a frequency range of 40 kHz–20 MHz.Dielectric properties of samples were measured by the dielectric sensor.Additionally,changes associated with fruit ripening properties,including firmness,total soluble solid(TSS)and pH were determined as a function of time at 2
C.The results showed that storage time significantly affected the quality characteristics of kiwifruit.Artificial neural networks(ANNs)were employed to develop models for prediction of quality indices from dielectric properties at the swept frequencies.Dielectric property features were selected as inputs while the quality indices including firmness,TSS and pH were chosen as output for the ANNs.The obtained models were able to predict the firmness,soluble solids content,and pH of kiwifruit non-destructively.Among predictive models,an ANN with a topology of 20-19-1 gave a perfect capability to predict the kiwifruit firmness with R2 value of 0.92.Results of this research show that this technique can be used as an efficient and non-destructive method for kiwifruit quality evaluation and monitoring the ripening.

Computerized recognition of pineapple grades using physicochemical properties and flicking sounds

Fruit is one of the essential sources of human nutrition.Consumers around the world need to be able to purchase fruit of reliable flavor and nutritional quality.Physical appearance and physicochemical properties play a key role in determining desirable quality and flavor.However,for some fruits such as watermelon,durian,pineapple,it is very hard to determine quality and flavor by external appearance.Therefore,a practical method to predict physical and physicochemical properties of fruit needs to be developed.In this study,a computerized technique is investigated to determine pineapple grades and their physical and physicochemical properties,including ripeness,total soluble solids,pH value and water content.The results reveal that by grading using pulp characteristics it is possible to classify pineapples into three distinct groups,which are significantly different in TSS,pH value and water content.In addition,predicting pineapple grades using flicking sounds and signal processing demonstrates that pineapples classified as grade 1 and grade 3 are significantly different in TSS,pH value and water content.This suggests that the estimation of the texture of pineapple pulp and its physicochemical properties can be performed prior to cutting.Therefore,it is feasible to develop an automated grading technique that can be used to determine pineapple quality as accurately as destructive grading to predict pineapple grades,texture and physicochemical properties.