Effect of some storage conditions on yield and technological quality characteristics of sugar beet at early and late sowing dates
under El.Minia Governorate conditions#
Ferweez, H. * and El.Dengawy.R.A **
*Sugar Crops Res. Inst., Agric. Res. Center, Egypt.
**Food Sci. and Techno. Dept., Fac. Agric. ,Assiut Univ. , Egypt.
ABSTRACT
Egyptian Government encourages sugar beet growers to increase the cultivated area of sugar beet for decreasing the gap between sugar production and consumption. The harvest period of sugar beet usually is compressed into a short period of time ,and large quantities of sugar beet roots are stored for some days prior to processing . This work carried out to study the effect of storage conditions on yield and technological quality characteristics of sugar beet at early and late sowing dates..Two field experiments were conducted at Malawi Agric.Res.,Station,Minia governorate,Egypt, during 2002/2003 and 2003/2004 seasons. Planting dates were on 15th September ( early sowing date)and 15th November( late sowing date). Storage periods ,zero time ,two ,four, six and eight days post- harvest and the five storage conditions :(I) open air condition (control ), (II)covering by tops ,(III) room storage ,(IV) treatment by Ca (O H )2 at 20% in open air field ,(V) treatment by Ca (O H )2 in room storage)
It could be concluded from the obtained results The decrease rate in root yield, recoverable sugar yield (ton/fed) and quality index of sugar beet were the lowest under treatment by Ca(OH)2 20% in store room followed by covering by tops among the studied storage conditions.. In addition, The decrease rate in rendement and pol % was the lowest as well as the increase rate in quality index of sugar beet
It could be concluded that with certain amount of risk, storage of beet roots is represented a more importance at late sowing date than the early sowing date. Generally , beet roots could be held only under treatment by Ca(OH)2 20% in store room or covering by tops were especially at the late sowing date if the processing delayed for any cause. It is not advisable to leave harvested roots under sun even for one dayunder El.Minia Governorate conditions as its lost significant weight .
Keywords: Sugar beet , storage period, storage conditions , sowing date and quality index.
------#Financed by the Regional Councils for Agricultural Research and Extension, Agricultural Research Center , Ministry of Agric. & Land Recl., Egypt, Middle and Upper Egypt Council for Research and Extension, Sids
INTRODUCTION
Sugar beet (Beta Vulgaris L.)isrepresented the second source for sugar production in Egypt , it is produced about 28.9% of the total sugar production in 2002/2003 season . Egyptian Government encourages sugar beet growers to increase the cultivated area of sugar beet for decreasing the gap between sugar production and consumption which reached 0.7 million ton annually (Gibriel,et.al.,2003; ESST,2003 and CCSC, 2003) .
Sucrose and quality losses in pile-stored sugar beet roots have financial implication for growers and processors alike . Most of sugar beet crop is planted in the winter and harvested in the spring and summer in Egypt . Such beet roots are grown mainly in temperate areas with relatively short growing seasons. Nevertheless , sugar beet roots must be removed from the ground at maturity and sugar factories must be run for several months to process the crop economically . Because of these factors , the harvest period usually is compressed into a short period of time , and large quantities of sugar beet roots are stored for some days prior to processing . For many years sugar beet agriculturists have been aware that significant amounts of recoverable sucrose were lost during such storage ( Martin,et.al.2001).
A more recent review was provided by Bugbee (1993) who summarized sucrose loss in storage , its causes and methods for reducing losses . In addition , Vukov & Hangyal (1985) and Harvey& Dutton,(1993) reviewed factors affecting roots quality and its relationship to storage and processing quality . Wyse and his co- workers(Wyse,1973;Wyse,1978;Wyse&Peterson ,1979 and Wyse, et. al.1979)pointed out the importance of respiration in storage losses. Besides , pre-harvest factor, i.e. sowing date affect sugar beet yield and its quality .
Backer, etal. (1979) Bugbee & Cole (1979) Akeson & Widner, (1981) and Mc Ginnis, etal. (1982) reported that beets lost sugar continously during storage. Many workers indicated that storage of sugar beet roots led to daily decrease in root yield, sugar yield and quality index , while sugar loss% , rendement ,pol%( WWB%), α-N ,Na and K contents of beet roots increased under the storage ( Mousa , 1990 ; Abou- Shady ,1994 and Nezam El.Din, 1996) .
Sugar beet plants grow well in the period from 1st September till 15th December under Middle and Upper Egypt. But, harvest periods of sugar beet are short and the hot environmental conditions found under Middle and Upper Egypt , i.e. El. Minia Governorate conditions , the period between the harvest and delivery of sugar beet roots to the factory will increase the chance for deterioration and increasing the loss in yield and technological quality characteristics of sugar beet if the processing delayed . Therefore , storage of beet roots is becoming necessary. The available information in respect to the presented problem is little . So , this study was carried out to face the problem and introduce the solve. Our objective of this investigation was to evaluate the effect of the different storage conditions on the loss in yield and technological quality characteristics of sugar beet post-harvest at early and late sowing dates.
MATERIAL AND METHODS
This investigation was carried out at the Mallawi Agricultural Research Station, El-Minia,Egypt, to evaluate the effect of the different storage conditions on the loss in yield and technological quality characteristics of sugar beet post-harvest at early and late sowing dates .This trial was laid out in a split plot design with four replicates. . Planting date was 15th September ( early sowing date)and 15th November( late sowing date) during the two seasons of 2002/2003 and 2003/2004 occupied in the main plots . The periods between yield delivery and the processing ,zero time ,two ,four, six and eight days post- harvest were occupied in the subplots and the five storage conditions treatments were allocated in the sub sub-plots. Gloria cultivar(Beta Vulgaris L.) was sown and all agricultural practices were carried in the same manner prevailing in the region except for the factors under work and harvested at 195 days of age .
Sampling for deterioration studies and storage conditions of sugar beet: Sampling for deterioration and storage studies of sugar beet :On the harvest day, A samples of about two and half tons from the roots of sugar beet cultivars were divided separately into five categories:(I) open air condition (control ), (II)covering by tops ,(III) room storage ,(IV) treatment by Ca (O H )2 in open air field ,(V) treatment by Ca (O H )2 in room storage. In the pervious categories, the roots of each category were placed as piles in four replicates, each containing about 100 kg of roots.Temperatures and relative humidities during the storage of beet roots, were recorded in Tables (1&2).
On the day of harvest and each two successive days up to eight days after harvesting, samples of roots (Twenty roots) from each stored category were sent for analysis are according to Mohamed, (2002). All determinations reported herein run in four replicates.
Sugar beet plants of The three guarded rows were topped, cleaned and weighted to determine :
1-Cleaned roots yield (ton/fed)as described in Abou-Salama & El.Syiad, (2000).
2-Recoverable sugar yield(ton/fed : It was calculated as in Mohamed, (2002), using the following formula:
3-Technological quality characteristics:
3.1-Rendement (Recoverablesugar per cent)was calculated using the following equation according to Abou-Shady (1994).
Rendement = Pol, % - [0.29 + 0.343 (K + Na) + - N (0.094)],
WhereK, Na and -N determined as milliequivalent/100 g beet.,
3.2-Quality index was calculated as in Abou- Salama and El-Syaid, (2000) using the following formula:
Quality index, % = Rendement,% X 100 ÷ Pol, %
3.3-Sucrose content or pol%was estimated in fresh samples of sugar beet roots cossettes, using saccharometer according to the method described in AOAC, (1995).
Allthe resultsobtained were tabulated and statistically analyzed according to procedure out lined by Snedecor & Cochran, (1980) and Gomez & Gomez (1983). Combined analysis between the two seasons was carried out .Significant of differences was defined at 5 per cent level .
Table (1): Meteorological data * during storage of beet roots, grown on15th September ( Early sowing date).
Storage period (day) /Temperature C
/ Relative Humidity %Unsheltered / Sheltered
Max. / Min. / Mean / Max. / Min. / Mean
0
1
2
3
4
5
6
7
8 / 40.0
36.6
43.0
43.0
37.0
35.0
33.0
36.6
40.1 / 11.8
9.0
8.0
10.6
12.8
10.8
8.6
9.0
7.4 / 25.9
22.8
25.5
26.8
24.9
22.9
20.8
22.8
23.8 / 27.6
26.0
23.0
33.8
29.2
25.4
24.0
26.2
33.4 / 14.6
12.4
12.0
14.8
16.0
13.8
12.2
12.4
11.8 / 20.6
19.5
22.1
24.3
22.9
19.7
18.3
19.4
22.8 / 66.0
68.0
69.0
56.0
64.0
68.0
72.0
70.0
53.0
Average
/ 38.3 / 9.8 / 24.0 / 28.6 / 13.3 / 21.0 / 65.1* Mallawi Meteorological Station, El-Minia, Egypt.
Table (2): Meteorological data * during storage of beet roots, grown on15th November( Late sowing date).
Storage period (day) /Temperature C
/ Relative Humidity %Unsheltered / Sheltered
Max. / Min. / Mean / Max. / Min. / Mean
0
1
2
3
4
5
6
7
8 / 49.6
51.6
52.6
47.4
45.8
45.8
46.0
52.8
45.0 / 19.2
17.0
17.6
21.0
19.0
17.8
18.0
18.4
22.0 / 34.4
34.3
35.1
34.2
32.4
31.8
32.0
35.6
33.5 / 36.4
40.2
40.4
37.6
36.4
36.2
37.0
40.0
35.6 / 23.2
20.6
22.8
24.6
23.0
22.4
22.8
23.4
24.8 / 29.8
30.4
31.6
31.1
29.7
29.3
29.9
31.7
30.2 / 67.0
49.0
44.0
51.0
60.0
53.0
58.0
51.0
60.0
Average
/ 48.5 / 18.9 / 33.7 / 37.8 / 23.1 / 30.4 / 54.8* Mallawi Meteorological Station, El-Minia, Egypt.
RESULTS AND DISCUSSION
A- Effect of storage conditions on roots and recoverable sugar yields of sugar beet at early and late sowing dates :
Data obtained in Table (3 &4) showed that beet roots (ton/fed)of sugar beet as average eight days of storage at all storage conditions significantly decreased by 6.55 and 19.70 % of the initial value at harvest with sowing sugar beet at early date on( 15th September) and late date (15th November), respectively. This means that the deterioration or loss rate in root yield (ton/fed.)of sugar beet at late sowing date was the higher at least 3- fold than early date . This might be attributed to the lower temperature at harvest in case of beet roots at early sowing date 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 by 6.74, 11.66 , 19.94 and 26.59%of the initial value at zero time after two, four, six and eight days, respectively . Wyse and his co-workers( Wyse,1973; Wyse,1978; Wyse & Peterson ,1979 and Wyse, et. al.1979) pointed out the importance of respiration in storage losses. Our findings are within the range of those found by Mousa, (1990) who declared that the percentage losses of roots yield increased significantly with increasing storage period. . Many workers indicated that storage of sugar beet roots led to daily decrease in root yield, under different storage conditions ,i.e. open air , covering by tops , normal store room , (Abou- Shady ,1994 and Nezam El.Din, 1996) .
Furthermore , the results presented in the aforementioned Tables(3&4), indicated that a significantly decreased in roots yield of sugar beet by 5.18, 6.81, 3.97 and 7.22 % of the control value{(I) Open air}compared with the other studied storage conditions, i.e, (II) Covering by tops, (III) room storage (IV) treatment by Ca(OH)2 at 20% in open air, (V) treatment by Ca(OH)2 at 20% in store room, respectively. The loss or deterioration rate in root yield of sugar beet was the lowest under treatment by Ca(OH)2 20% in store room and covering by tops among the studied storage conditions. Such results are in good agreement with those obtained by Sobkowicz & Lisinska (1979); Frost (1982); Bugbee, (1993) who stated that roots temperatures were lowered when milk of lime was applied to the outer layer of piles roots. The white colour of the lime reflected sunlight and high pH reduced decay from storage rot pathogens
Statistical analysis of results recorded in Tables( 5&6) showed that recoverable sugar yield (ton/fed)of sugar beet as average eight days of storage at all storage conditions significantly decreased by 5.38 and 17.90%of the initial value at harvest with sowing sugar beet at early and late dates, respectively .This might be attributed to the decrease in beet roots and the increase in the rendement of sugar beet were the lowest at early than late sowing date . In the same subject, there was significantly decrease in recoverable sugar yield of sugar beet by 5.94, 10.40 , 16.75 and 22.19 %of the initial value at zero time after two, four, six and eight days, respectively . Backer, etal. (1979) Bugbee & Cole (1979) Akeson & Widner, (1981) and Mc Ginnis, etal. (1982) reported that beets lost sugar continuously during storage. These findings are in agreement with those obtained by Abou-Shady, (1994) and Mohamed,(2002) who revealed that the minimal losses of recoverable sugar yield were recorded in fast processed sugar beet . Here too , the results recorded in the aforementioned Tables , clarified that a significantly increase in recoverable sugar yield of sugar beet by 4.37, 5.66, 3.09 and 5.91 % of the control value {Open air conditions}with the other studied storage conditions, i.e, (II) Covering by tops, (III) room storage (IV) treatment by Ca(OH)2 at 20% in open air, (V) treatment by Ca(OH)2 at 20% in store room, respectively. The deterioration rate in root yield of sugar beet was the lowest under treatment by Ca(OH)2 20% in store room among the studied storage conditions. Such findings are in harmony with those reported by Abou-Shady (1994) and Mohamed(2002) who revealed that sugar beet roots stored by milk of lime and covering by tops had the lowest deterioration rate in recoverable sugar yield (ton/fed).
B- Effect of storage conditions on technological quality characteristics of sugar beet at early and late sowing dates :
Concerning sowing date effect ontechnological quality characteristics of sugar beet at early and late dates,the results recorded in Tables(7-9) indicated that rendement of sugar beet as average eight days of storage at all storage conditions significantly increased by1.19 and 1.72% as well as pol% of sugar beet by 2.51and 3.98% of the initial value at harvest,while quality index of sugar beet significantly decreased by 1.43 and 2.23% of the initial value at harvest with sowing sugar beet at early and late dates,respectively .This observations might be attributed to differences in the environment influence at early and late sowing datesof sugar beet as well as during the storage . The increase in rendement and pol% of sugar beet might be due to a slight increase in concentration of TSS,% as a result of the loss in moisture% of beet roots during the storage .While the decrease in quality index of beet roots might be due to increasing the impurities in roots juice of beet roots was higher than the increase in the pol% of sugar beet(on WWB). Generally, the decrease in quality index of beet roots and the increase in the rendement and pol% of sugar beet were the lowest at early than late sowing date These results are in line with those reported by, Vukov & Hangyal (1985) and Harvey& Dutton,(1993)who reviewed factors affecting roots quality and its relationship to storage and processing quality.
Results given in Tables (7-9), clarified that there was significantly increase in rendement of sugar beet by 0.56, 0.77, 2.38 and 3.22 % as well as pol% of sugar beet by 1.78,2.86,3.78 and 6.53%, while quality index of sugar beet significantly decreased by 1.20,2.16,2.52 and 3.10% of the initial value at zero time after two, four, six and eight days of storage, respectively. These findings are in agreement with those obtained by Dilly,et.al.(1970)reported that the loss of sugar from sugar beet during storage is significant economic factor .Here too, Abou-Shady,(1994) and Mohamed,(2002) revealed that the minimal losses of recoverable sugar yield were recorded in fast processed sugar beet . For many years sugar beet agriculturists have been aware that significant amounts of recoverable sucrose were lost during such storage (Martin,et.al.2001).They added that sucrose and quality losses in pile-stored sugar beet roots have financial implication for growers and processors alike.
The results recorded in the aforementioned Tables(7-9) , pointed out that a significantly decrease in rendement of sugar beet by 0.76, 1.11, 1.11 and 1.25 % as well as pol% of sugar beet by 1.61,2.12,1.50 and3.62% of the control value {Open air conditions},while quality index of sugar beet significantly increased by 0.72,1.08,0.53 and 1.41%of the control value {Open air conditions}with the other studied storage conditions, i.e, (II) Covering by tops, (III) room storage (IV) treatment by Ca(OH)2 at 20% in open air, (V) treatment by Ca(OH)2 at 20% in store room, respectively. The decrease rate in rendement and pol% was the lowest as well as the increase rate in quality index of sugar beet was the highest under treatment by Ca(OH)2 20% in store room among the studied storage conditions . Such findings are in harmony with those reported by Madalageri,(1974) who revealed that loss of sucrose for first two days was low under room temperature.. In the same subject, Gouda (1988) stated that storage of healthy beet roots under proper conditions caused losses of sucrose contents and consequently reduction in quality index of beet roots. In Addition, Mousa (1990) and Bugbee (1993) who summarized sucrose loss in storage , its causes and methods for reducing losses .Abou-Shady (1994) indicated that the relative increase in rendement of beet roots under covering by tops was the lowest than of open air and store room conditions .sugar beet roots stored by milk of lime and covering by tops had the lowest deterioration rate in recoverable sugar yield (ton/fed). Adequate humidity retarded roots dehydration and promotes wound (Mohamed ,2002) .He added that successful attainment of proper temperature and humidity does more than other storage operation to conserve sucrose.
C. Some economic of sugar beet productivity per feddan under some storage conditions at early and late sowing dates :
It is concluded from the data in Table (10) that the total return per fed. was markedly increased at early sowing date (on 15th September) by 17.37 %of the initial value as mean eight days of storage over at late sowing date (on 15thNovember).Also, net profit at early sowing date, was increased by 78.72 % of the initial value as average eight days of storage over at late sowing date. In addition ,root yield in ton / 1000 m3 of water increased at early sowing date by 17.40 % ,while, Sugar yield (in ton )/ 1000 m3 of water increased by 33.03% of the initial value as average eight days of storage over at late sowing date. This is led to inhancing the efficiency of water use and early sowing importance of sugar beet under El.Minia governorate conditions to reducing the losses of roots and recoverable sugar yield post-harvest and during the storage of beet roots .