7- Materials and Methods

Effect of delaying the delivery of roots yield to factory on the loss in yield and quality of sugar beet at different sowing dates under El.Minia Governorate conditions

Ferweez , H.M. * and Khalifa,A.H.**

*Sugar Crops Res. Inst., Agric. Res. Center, Egypt.

**Food Sci. and Techno. Dept., Fac. Agric. ,Assiut Univ. , Egypt.

ABSTRACT

A lot of growers left roots yield in the fields under the open air conditions to increase of pol,%of beet roots and consequently increasing the return per ton of beet roots . But, this is not recommended because the reduction in roots yield by ton is higher than the return resulted in an increase of pol, % of beet root . In addition ,this led to a lot of the problems during the processing . So, this work carried out to study the effect of delaying the delivery of roots yield to factoryon yield and quality of sugar beet post-harvest at different sowing dates.Two field experiments were conducted at Malawi Agric.Res.,Station,Minia governorate, Egypt. during 2002/2003 and 2003/2004 seasons. Sowing dates were 15/9 ,15/10 and 15/11,while, delaying periods were zero time (at harvest ) ,two ,four , six and eight days. It could be concluded from the obtained results that The deterioration rate in root yield (ton/fed.) and recoverable sugar yield (ton/fed) post-harvest with sowing sugar beet on 15th September and 15th October was the lowest followed by sowing November, respectively. In addition, a gradual and significant decrease in the quality index of sugar beet while a significantly increase in rendement , sugar loss% ,pol %,alpha amino nitrogen , potassium and sodium contents of sugar beet with delaying the processingwere recorded. Decrease rate in root and recoverable sugar yield (ton/fed.) of sugar beet post-harvest as a result of sowing date was the highest followedbythe delaying periods. . Therefore, sowing sugar beet on 15th September and15th October with quickly processing for beet roots have the following advantages :1)Increasing the grower income, 2)Increase the efficiency of water use , 3)Increase the sugar production and reduce the vast gab between sugar consumption and production .

Keywords: sugar beet ,delaying period, sowing date , deterioration and rendement..

INTRODUCTION

Sugar beet is the second crop in the world and Egypt for sugar production. The cultivated sugar beet in the world estimated by 14.35 million fed. In Egypt the total area of sugar beet in 2003 was estimated about 153800 fed. Produced about 3.17 million tons with an average of 20.60 tons/fed(CCSC, 2003 and ESST, 2003). Beet sugar factory management endeavours to keep their plant going with a regular supply of fresh beets from the fields to avoid storage and consequent sugar loss. When the beet crop is heavy because of the short harvest period, storage is unavoidable.In this subject, Scott & Jaggard, (1993); Ali (1993); Elliott & Weston (1993); Gutmanski & Nowakowski, (1994); Besheit, etal. (1994)Mousa,(1990);Abou-Shady(1994)and El.Sharnouby, et al.(1999) demonstrated that there was loss in root daily weight of sugar beet roots as a result of delaying the processing.

From the botanical point of veiw, it is well known that harvested beets are living tissues. It consumed sugars during respiration in order to mention life as all living organisms. Increasing the temperature about 15 F than at 35 F would double the amount in sugar lost. Removal hazards of storage was the primary problem of commercial storage improvement. Sugar losses during storage resulted from two general causes: (1) Through the general process of respiration of the living tissues of the beet, (2) By spoilage through the action of invading organisms, principally certain species of fungi (Stout, etal. 1951; Cottrell, 1952 and Wooley & Bennet, 1962). On the other hand, Backer, etal. (1979) Bugbee & Cole (1979) Akeson & Widner, (1981) and Mc Ginnis, etal. (1982) ; Carter, etal. (1985); Besheit, (1986); reported that beets lost sugar continously during storage with the highest rates of loss occurring the first 30 days of storage because of harvest wounds and higher pile temperature. A second important factor influencing sugar loss was beet temperature. The aim of this trial was to define the effect of the period between the harvest and processing of beet roots sown in different dates on yield and technological quality characteristics of sugar beet roots as raw material for sugar production.Where ,there is found a lot of growers which leave roots in the open air to increase of pol,%of beet roots and consequently increasing the return per ton of beet roots . But this is not recommended because that the reduction in roots yield by ton is lower than the return resulted in an increase of pol, % of beet root . In addition ,this work led to a lot of the problems during the processing as a result of an increases in the impurities and consequently ,decrease in sugar production.

MATERIALS AND METHODS

This work was conducted at the Mallawi Agricultural Research Station, El-Minia, Egypt,during two seasons 2002/2003 and 2003/ 2004 growing seasons , to study some factors which affect of the loss of sugar beet post-harvest such as planting date and delaying the crop delivery to factory in split plot design . Planting dates were 15/9 ,15/10 and 15/11 . Delaying periods of yield delivery to factory were zero time (at harvest ) ,two ,four , six and eight days post- harvest .

Sampling for deterioration studies of sugar beet :On the harvest day (age 195 days from sowing date), a sample of about half ton approximately from the healthy and vegetative homogenous beet roots of sugar beet cultivar namely Gloria in four replicates, topped, cleaned and thoroughly mixed into a pile. Beet roots piles were left under open field conditions in the deterioration studies at different sowing dates. Temperatures and relative humidities during the storage of beet roots, were recorded in Tables (1).

On the day of harvest and each two successive days up to eight days after harvesting, samples of roots (Twenty roots) from sugar beet in each stored category were sent for analysis according to Mohamed, (2002).

Plants of sugar beet were topped, cleaned and weighted to determine cleaned roots yield (ton/fed.) as described in Abou-El-Magd, (1998),while recoverable sugar yieldwas calculated as in Abou-Shady, (1994), using the following formula:

Recoverable sugar yield (ton/fed.) = Cleaned roots yield (ton/fed.) X Rendement.

Roots samples were cleaned with running tap water, dried, each sample was grated separately with grater into cossettes and mixed thoroughly as described in Cooke & Scott, (1993). All determinations reported herein run in four replicates and results were expressed as a mean of two seasons.

The following characters were determined for physical evaluation of beet roots cossettes,rendement (Recoverable sugar per cent)was calculated using the following

equation according to Mohamed (2002).

Rendement = Pol, % - [0.29 + 0.343 (K + Na) +  - N (0.094)]

Table (1): Meteorological data * during deterioration of beet roots post-harvest at different sowing .

Average

* Mallawi Meteorological Station, El-Minia, Egypt.

Where, K, Na and  - N determined as milliequivalent/100 g beet.Sugar loss per cent was calculated using the following formula acvording to Abou-Shady, (1994).

Sugar loss per cent = Pol,% - Rendement ,%.Quality index : It was calculated as in Abou-Salama and El-Syaid, (2000) using the following formula:

Quality index, % = Rendement,% X 100 ÷ Pol, %

The following constituents were estimated for chemical analysis of beet roots cossettes, Sucrose contentwas estimated in fresh samples of sugar beet roots, using saccharometer according to the method described in AOAC, (1995).

While ,alpha amino nitrogen, sodium and potassium contents were estimated according to the procedure of sugar company by Auto Analyzer as describle in Cooke and Scott, (1993). The results calculated as milliequivalent per 100 gm beet.Data collected were subjected to Analysis of Variance (ANOVA). The proper statistical of all data was carried out according. Differences among treatments were evaluated by the least significant difference test (LSD) according to procedure out lined by Snedecor & Cochran, (1980) and Gomez & Gomez (1983). Significant of differences was defined at 5 per cent level according to Waller and Duncan (1969).

RESULTS AND DISCUSSION

A- Roots and recoverable sugar yields :

The results recorded in Table (2) showed that beet roots harvested at 195 days of age decreased by 10.55, 18.65 and 26.65% of the initial value after eight days as mean valuewith sowing sugar beet on 15th September, October and November, respectively. The deterioration or loss rate in root yield (ton/fed.) post-harvest with sowing sugar beet on 15th September was the lowest followed by sowing 15th October and November, respectively. This might be attributed to the lowest temperature at harvest in case of beet roots sown in 15th September reduced the relative losses in moisture content and sucrose consumption post-harvest as a result of respiration process for beet roots.In addition,there was significantly decrease in roots yield of sugar beet with increasing the delaying period as shown in Table (2). Data for this character referred root yield (ton/fed.) decreased by 6.63, 15.46, 25.98 and 33.86% of the initial value after two, four, six and eight days, respectively. Our findings are within the range of those found by Mousa, (1990) ; Abou-Shady, (1994) and Mohamed, (2002) who declared that the percentage losses of roots yield

increased significantly with increasing the period between harvesting and processing.

The data recorded in Table (3) referred that recoverable sugar yield of sugar beet was affected significantly by sowing date. The data showed that recoverable

sugar yield of beet roots decreased by 8.76, 16.60 and 23.63% of the initial value

Table (2) : Effect of delaying the delivery on roots yield(ton /fed.) of sugar beet sown

in different dates.

A=0.30 B=013 AB=NS

after eight days as mean value with the three studied sowing dates respectively.This result might be due to reducing normal process of respiration of the living tissues for beet roots because reduction of temperature at harvest in case of beet roots sown on 15th, September than 15thOctober and 15th November,respectively.The lowest temperature at harvest in case of beet roots sown in 15th September reduced the relative losses in moisture content and sucrose consumption post-harvest as a result of respiration process for beet roots.So,sowing sugar beet on 15th November recorded the highest relative loss in recoverablesugar yield(ton/fed.)of sugar beet post-harvest. The listed data in the same Table , clarified that a significant decrease in recoverable sugar yield (ton/fed.) of sugar beet with increasing the period between harvesting and processing.Data for this character referred that recoverable sugar yield (ton/fed) of sugar beet decreased by 8.91, 16.71, 25.39 and 32.16 % of the initial value after two, four, six and eight days of delaying ,respectively. Such results are in accordance with those obtained by Mohamed , (2002) who indicated that the loss,%

Table (3) : Effect of delaying the delivery on recoverable sugar yield (ton/fad.)

of sugar beet sown in different dates.

in recoverable sugar yield (ton/fed.) of sugar beet increased significantly with

increasing the period between harvesting and processing .

It could be concluded that from the aforementioned results, the decrease rate in root and recoverable sugar yield (ton/fed.) of sugar beet post-harvest as a result of sowing date was the highest followed by the delaying periods. Fayed, etal. (1981); El-Gharbawy, etal. (1981) and Frost, (1982) demonstrated that as a rule of Thum beets in areas where average daily temperature exceeded 40 C should be processed with no more than a few hours of storage. In areas where ambient temperature are 25 to 35 C, storage should be limited to 2 or 3 days. He added that, in any case before storage the beets should be cleaned by passing over the dirt screens so that there would be voids between the beets to permit natural or forced ventilation of the piles.

B- Physical Properties :

The data given in Tables (4 ) showed that rendement of sugar beet was affected significantly by sowing date. The data showed that rendement of beet roots increased by 1.65, 1.81 and 2.84% of the initial value after eight days as mean value with the three studied sowing dates, respectively.This increase might be due to that the loss in the moisture content of beet roots was higher than the loss in the sucrose content on

Table (4) : Effect of delaying the delivery on rendement of sugar beet sown in

different dates.

wetweight basis ,consequently the increase in the pol % .This led to an increase in rendement of beet roots. The relative increase in rendement of beet roots was the lowest with sowing sugar beet on 15th October followed by 15th September and 15th November, respectively.This might be due to that the lowest relative loss in the moisture content of beet roots was found with sowing sugar beet on 15th October .These findings ran with those recorded by Abou-Shady (1994).

The results presented in the same Table (4)revealed that a significant inecrease in rendement of sugar beet was found between the studied delaying periods and sowing dates. Data for this character referred that rendement of sugar beet increased by 0.88, 1.75, 3.50 and 4.24 % of the initial value after two, four, six and eight days of delaying , respectively. The data obtained had the same trend of that reported by Mohamed , (2002) who referred that there was an increase in rendement of sugar beet with increasing the period between the harvesting and processing.

Data tabulated in Tables (5) showed that sowing date of sugar beet after eight days post-harvest had a significant effect on sugar loss %. The data showed that sugar loss % of beet roots increased by 12.38, 13.59 and 20.12 % of the initial value after eight days post-harvest as mean value with the three studied sowing dates,

Table (5) : Effect of delaying the delivery on sugar loss,% of sugar beet sown

in different dates.

respectively. This an increase might be due to increasing the impurities,i.e. alpha amino nitrogen ,potassium and sodium contents of beet roots . The relative increase in sugar loss % of beet roots was the lowest with sowing sugar beet on 15th September followed by 15th October and November, respectively.This might be due to that the lowest relative loss in the moisture content of beet roots was found with sowing sugar beet on 15th September.These findings ran with those recorded by Abou-Shady (1994). Concerning effect of the period between the harvesting and processing on sugar loss,% sugar beet,the results given in Table (5) revealed that sugar loss % of beet roots was significantly increased by 10.13, 17.41, 23.10and 26.58 % of the initial value after two, four, six and eight days of delaying , respectively. These data are in good accordance with those of Mc Ginnis ,et al., (1982) who concluded that respiration could account for 80.00% of loss of sucrose .They added that a second source of sugar loss is the biochemical conversion to other metabolites, primarily invert sugar and raffinose .So, the increase in prolongation of period after harvesting sugar beet is not recommended .

A gradual and significant decrease in the quality index of sugar beet post-harvestas sowing date latedas shown in Table (6 ) .Where quality index of sugar beet was decreased by 1.84, 1.81 and 3.27 % of the initial value after eight days post-harvest as mean value with the three studied sowing dates, respectively.This decrease might be due to increasing the impurities. These findings ran with those recorded by Abou-Shady (1994). From the data recorded in the same Table ,indicated that the period between the harvesting and processing had a significant effect on quality index of beet roots. Quality index of beet roots was decreased by 1.68, 2.77, 3.34 and 3.78 % of the initial value after two, four, six and eight days of delaying , respectively. This might be due to that the relative increase in sugar loss % of beet roots with delaying the processing time . These findings are in the same trend with those published by Mohamed , (2002) who indicated a gradual and significant decrease in

the quality index when the delivery of roots to the factory late.

Table (6) : Effect of delaying the delivery on quality index of sugar beet sown

in different dates.

C.Chemical composition :

Moisture% of sugar beet was significantly decreased by 4.98,6.00 and 9.43 %of the initial value after eight daysof delaying as mean value with the three studied sowing dates, respectively as shown inTable (7) .With regard to effect of the period between the harvest and processing on moisture,% sugar beet,the results revealed that

Table (7) : Effect of delaying the processing on moisture,% of sugar beet at different

sowing date.

Table (8) : Effect of delaying the processing on pol,% (on WWB,%)*of sugar beet at different