processing

Tea, this popular drink is produced in several ways, one of the methods used in Iran for tea processing is the orthodox method. In this method, the tea is first added and then rubbed, and after passing through the fermentation period, it enters the dryer. In order to check the quality of tea in the rubbing section, this research has evaluated the two parameters of the speed and the distance of the cylinder from the bottom of the machine. To investigate the effect of the speed and distance of the cylinder on the quality of the final tea, first, using Solidwork software, a device similar to rubbing tea in the orthodox way with a capacity of 10 kg was designed and built. After weighing, the samples were divided into 10 kg parts and rubbed 27 times with speeds of 20, 30 and 40 rpm and distances of 2, 3 and 4 cm and with a 10 kg household tea rubbing machine. The rubbed samples were examined in terms of failure percentage and rubbing time. According to the analysis of the results and the analysis of the average comparison tables, it was observed that there is a significant difference between the values of percentage of failure and time in the constant cycle, among all the distance levels, and the lower the distance of the cylinder from the bottom of the machine, the higher the percentage of failure and the rubbing time. It will be shorter. At a fixed distance between some levels of rotation speed, there is no significant difference between the time values, which varies according to the distance, but the failure percentage values at a fixed distance are significantly different from each other, and the higher the rotation speed, the higher the percentage of failure. . Due to the need for speed in carrying out the process while maintaining quality, the recommended speed and distance is 20 revolutions per minute (RPM) and the distance is 3 cm.

Oilseeds after cereals ranked at second place as human’s food sources. Among them, sunflower is one of the main oilseed for cultivation. Because of increasing demand rate for edible oil import, it is necessary to avoid any grain loss during harvesting and processing of oilseeds. In some sunflower fields, mechanical harvesting is hardly done by combines due to difficulty for movement as well as the small-cultivated area. Then, manual harvesting and processing of sunflower heads and grains are appropriate and most used field operations. Detachments of grains from heads is a tedious work and labor-intensive operation. Also, form medical and ergonomic point of views it makes physical problem for workers. All commercial equipment thrash field dried sunflower heads, entirely. Therefore, some wastes are produced at preharvest (in field), threshing and separation processes. Some research have been conducted to adjust combine to decrease grain losses. Cylinder rotational speed and type, distance between cylinder and concave, heads moisture content and threshing unit feed rate were such adjustment. However, none of the detached grains from head without head threshing. On the other hand, losses to about ‎‏46% during harvesting the ‎sunflowers with the combine, a partially mechanized approach for grain detachment was chosen in this study. ‎

To do this an existing sunflower seed detacher unit (Jahani, 2014) was equipped with cleaning unit. In addition, the unit efficiency was improved by optimizing the device settings. This device consisted of a feeding conveyor belt, two series detacher cylinder with 8 cm rubber fingers covered all through their peripherals in segregated patterns, cleaning unit, two electric motor and deriving mechanism (belt and pulley). Cleaning unit comprised an axial flow fan and an inclined guide canal for grain movement. Fan was selected in such a way that separate the gross waste materials mixed with grain, detached from heads by laboratory test using a terminal velocity test rig. Slope and material of canal was determined by laboratory trials using a test rig to measure sliding coefficient of grain batches. For evaluating the unit performance, laboratory experiment was carried out at four levels of rotational speed of the detacher cylinders (300, 450, 510 and 600 rpm) and four levels of grain moisture content (7, 15, 20 and 27% db) in three replications. Cylinder rotational speed and feeding belt speed were selected based on Janani’s research results. Feeding belt speeds were adjusted in such a way that the speed ration of linear velocity of cylinders to feeding belt were constant and about 72.2 as reported by Jahani (2014). Moisture content levels were considered based on harvesting, processing and storage conditions of sunflower grains. Raw data were used to compute percentage of seed detachment, percentage of separation and grain fracture percentage.

ANOVA revealed that main factors of cylinders rotational speed and moisture contents and their interaction significantly affected percentage of separation (p < 0.01). Increasing in moisture content reduced the amount of detached grains from head due to flexibility of grains at higher moisture content and damping impact of rubber fingers. In addition, it was reported that lower moisture content produced lower adhesive force between grain outer surface and the pod. On the hand, increasing in rotational speed increased the amount of detached seed because of impact of rubber fingers and stored kinetic energy in shelled grains. The most detaching was obtained at 600 rpm and 5% moisture content. The rotational speed and grain moisture content and their interaction significantly (p < 0.01) affected percentage of fractured grains. Moisture content had more share for grain failure than rotational speed. Higher fracture was observed at lower moisture contents and higher cylinder speeds, so that it was around 6.4% at 600 rpm and 7% moisture. According to the results, cleaning was affected by moisture content alone and higher percentage took place at lower moisture contents because of lighter produced wastes. Overall, considering all above aforementioned indices, cylinder rotational speed of 600 rpm and grain moisture content of 20 % was the appropriate adjustment set for grain detaching. In such adjustment, detachment rate was as high as 94.6 %, grain fracture was limited to 0.27 %, cleaning was 68 % and the output capacity of the machine of 268 kgh-1 was achieved. More adjustment on fan speed is required to increase the rate of cleaning to approach hundred percent of cleanness.

The improving of black tea quality has always been in the goals of the tea industry in Iran. In this study, two tea processing techniques (Orthodox and CTC) were used to make black tea with passing Orthodox tea through CTC roller. The treatments consisted of the Orthodox rolling time (one and two times) and the time of passes CTC (two and four times). The first and second on sieve tea were used as the first and second controls after drying. Chemical quality of made tea from combining methods consisted of theaflavin, thearubigin, theaflavin to thearubigin ratio and aqueous extract were improved (p<0.05). It was no significant in time of passes through CTC. The sensory evaluation indicated the use of combination method improved sensory characteristics in made tea, including appearance, color, taste, aroma and total score, while tea appearance was undesirable (p<0.05). Made tea from first on sieve tea passed CTC has significantly better than other treatments in sensory quality. The value of made tea from combining methods were higher than two controls.

Dehulling is an important step in walnut processing that has considerable effect on the quality, chemical and microbial properties of walnuts. Improving dehulling can increase the quality of the final product. This research studied the effect of genotype and hulling method on walnut properties. Oneexperiment was performed as a factorial in a randomized complete block design with three replications in the food industrial laboratory of the Agricultural Research Center in Kerman. Chemical (fat oxidation, percent of moisture), aflatoxin and sensorial (color, taste, general acceptance) properties of seven genotypes (20, 21, 77, 88, 95, 211, 264) and their kernels were evaluated using two walnut hulling methods (industrial and traditional). The data were analyzed in and compared using a Duncan t test at p = 5%. The results showed minimum fat oxidation in walnut samples for genotypes 95 and 264 and in kernel samples for genotype 264. Moisture content in all samples was in the required range and the hulling methods for genotype 21 had minimum fat oxidation. The study showed that genotypes 77, 88 and 264 had the toughest skin and no aflatoxin was observed in these genotypes. Walnut samples 21 and 88 and kernel genotypes 24, 21 and 88 had the best taste and color. Hulling method had no significant effect on the sensorial properties of the walnut and kernel samples. Interaction between treatments showed that the industrial hulling method with genotype 21 was better for both walnuts and kernels. The sensorial and chemical properties of genotype 21 are more suitable for cultivation and, because there was no aflatoxin detected in industrial hulling, this method is most effective for processing walnuts.