Difference between revisions of "Rice (incl. transport guidelines)"

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Revision as of 11:51, 11 July 2012

Infobox on Rice (incl. transport guidelines)
Example of Rice (incl. transport guidelines)
Rice.jpg
Facts
Origin This table shows only a selection of the most important countries of origin and should not be thought of as exhaustive.
  • Europe: France, Italy, Hungary
  • Africa: Egypt
  • Asia: Burma, China, Pakistan, Thailand, India; East and South-East Asia being the main areas of cultivation.
  • America: Argentina, Uruguay
  • Australia
Stowage factor (in m3/t)
  • 1.359 m3/t (bulk cargo)
  • 1.5 - 1.6 m3/t (jute fabric bags, 100 kg)
  • 1.81 - 1.95 m3/t (paddy rice, bags or bulk)
  • 1.34 - 1.39 m3/t (cargo rice, bags or bulk)
  • 1.39 - 1.45 m3/t (white rice, bags or bulk)
  • 1.48 - 1.56 m3/t (broken rice, bags or bulk)
  • 1.84 - 2.12 m3/t (rice, unhulled)
  • 1.44 - 1.56 m3/t (rice, hulled)
  • 1.39 - 1.56 m3/t (rice, polished)
Angle of repose -
Humidity / moisture
  • Relative humidity: 70%
  • Water content: 13 - 15%
  • Maximum equilibrium moisture content: 70%
Oil content -
Ventilation Loading as bulk cargo: surface ventilation.
Loading as general cargo: air exchange rate 15 - 25 changes/hour. Good surface ventilation and airing are necessary.
Risk factors At an excessively high water content in particular, rice has a tendency towards self-heating. Water contents of > 15% and relative humidities of > 75% result in self-heating of the cargo due to hydrolytic/enzymatic fat cleavage.
Rice is highly odor-sensitive, prone to contamination and shrinkage. Beware of infestation.

Rice (incl. transport guidelines)

Transport guidance on bagged rice

As a cereal grain, rice is the most important staple food for a large part of the world's human population, especially in Asia and the West Indies. It is the grain with the second-highest worldwide production, after maize (corn).

Since a large portion of maize crops are grown for purposes other than human consumption, rice is the most important grain with regard to human nutrition and caloric intake, providing more than one fifth of the calories consumed worldwide by the human species.

Therefore we have extended the article on rice to a transport guidance, in order to prevent loss as much as possible.

Introduction

1.1 Types of rice cargoes

Rice, or Oryza, can vary in height from 1 – 6 m. It is an extremely adaptable plant; it has an efficient system of air passages connecting the roots and the shoot. This enables it to grow in dry upland soils, in irrigated fields, or along flooded river beds, Rice is largely self-pollinated, but cross-pollination does occur in degrees ranging between 1 – 30%.

There are over 85.000 varieties of rice in the research stocks of the International Rice Research Institute (IRRI), and there are over 120.000 cultivars known to exist. The familiar distinctions to Westerners of long grain versus short grain, or white versus brown, are but two. Like wheat, oats or maize, rice is a cereal. It is a basic diet for over 50% of the world’s population and is therefore the most important crop in the world. The range of varieties is so great that no internationally recognised system of classification exists, although repeated efforts have been made since the Rice Congress at Valencia in 1914 urged ‘the formation of a real botanical classification of the varieties of cultivated rice’. Two species are cultivated, Oryza sativa and Oryza glaberrima (wild rice – in West Africa).

Asian rice, Oryza sativa, is divided into two categories, both of which include glutinous and non-glutinous varieties. Indica rices’ grains are longer and more slender, and they usually remain separate when cooked. Japonicas have shorter, rounder and more translucent grains which quickly become slightly sticky. Indica grains are divided into medium (5 – 6 mm) or long grain (more than 6 mm). It was proposed in 1958 to coin another name, javanica, for the bulu and gundil varieties of Indonesia. Most rices grown in the tropical zones belong to the indica and javanica groups, which tend to have a fixed growth period. Japonia rices have shorter grains (4 – 5 mm) and are also different in terms of taste and smell. They are highly sensitive to photoperiod, or day length, and so do poorly in the short-day tropics. They are, however, widely grown in N. China, Korea and Japan. Then there is glutinous rice, (Oryza sativa L. glutinosa) which is specified as having a starch level of 99$ amylopectine. The grains are completely opaque, and this rice tends to be reserved by Asian populations for confectionery and cakes.

The long grain varieties, Oryza indica, tend to be preferred by the people of Inda and SE Asia; the Japanese and Indonesians prefer the stickier, short grained variety Oryza japonica. Rice plants are usually grown in flooded fields known as paddies, although there are varieties which can be grown ‘dry’, for example in Tanzania, Zambia and the Philippines – these tend to produce a lower yield, however. The roots of the rice plants are kept underwater. The head of the plant, known as the panicle, contains small spikelets which produce grains of raw rice, known as paddy.

Before the paddy field is flooded, the soil needs to be broken up and levelled. In most rice-growing countries, the seeds are first sown in nurseries. Small corners of the paddies are set aside for sowing. On the first night, the seeds are often kept in water, to allow germination, then planted. About 30 days later, the rice plants are pressed into the mud in rows. The rice plants are often under attack from weeds or pests such as rats, worms, birds and snails – hence there are often fish in the paddy fields. Fish are no protection, however, against the other threats of hurricane, drought or rats.

Rice matures very quickly in the right growing conditions. The life cycle of the rice plant is generally 100 – 210 days; the average falls between 110 – 115 days. In temperate climates the average duration from sowing to harvest is about 130 – 150 days. Cultivars with growth duration of 150 – 210 days are usually photoperiod sensitive and are planted in the deepwater areas. Temperature and day length are the two environmental factors affecting the development of the rice plant, which can be divided into three phases:

  • Vegetative – from seed germination to panicle initiation;
  • Reproductive – from panicle initiation to anthesis;
  • Ripening – from anthesis to full maturity.

Controlled irrigation dramatically improves yields – most rice needs between 250 – 600 grams of water for each grain of rice eventually formed. When ready for harvesting, rice is a golden yellow. Combine harvesters can cut the rice, separate the grain from the straw, and leave the straw in the field.

When harvested, rice typically contains from 15 – 22% (US) or 19 – 25% (Asian) moisture and therefore must be dried to a moisture content of 12 – 14% to prevent spoilage. The rice dries in the sun, or it can be dried by blowing hot air through piled sacks of grain, which reduces the risk of disaster from sudden torrential rain. Paddy is then stored to protect it from damp, heat, rodents, insects, birds and fungi; it can be stored in large pots or bamboo baskets, or in lofts or barns on stilts. Rice can be stored for years. Modern steel or concrete silos automatically control the humidity and temperature of the vast amounts of paddy which they contain.

After being dried and stored, the rice goes through the milling process, which removes the tough outer husk and inner layers of bran from the edible rice grain. Unfortunately, milling also removes much of the goodness, hence the gradually increasing demand for brown rice. However, most consumers like white rice, so the grain is also polished white, and sometimes also glazed with glucose and talc. From 100 kg of paddy (rough rice), 20 kg of husk and 80 kg of brown, de-husked rice can be obtained. From the milling process, 68 kg of milled rice (or parboiled rice, where the rough rice is exposed to steam pressure and the grain becomes harder and less sticky) and 12 kg of bran and other by-products are obtained. From the 68 kg, 55 kg can be expected to be wholegrain and 13 kg broken grain.

Rice is traded either as paddy or milled rice and an indication is needed in the description of the product i.e. paddy/brown/milled/parboiled. Other mentions needed are grain type (long or short), origin and the percentage of broken rice, for instance, Thai white rice long grain 5% broken.

Electronic sorting machines can classify the size, type and colour of each batch of rice and separate the different grades for packaging. The main patterns of good quality are:

  • Colour – as white as possible (no discolouration, no imperfections);
  • Whole grains – minimum percentage or broken grain.

Standards in most countries define the percentage of brokens and other imperfections allowed in each grade of rice, and the basis on which such percentages are measured.

1.2 Composition and nutritional value

The composition and nutritional value of rice varies with the nature of the soil, climate, variety, the conditions of culture – in particular the fertilizers used, etc; this it has in common with all vegetables and grains. But for rice in particular, the nutritional value depends on the degree of milling that is undertaken. Brown rice contains 8% protein, 70% starch and small quantities of lipids, fibre and minerals. After milling, however, the decline in beneficial elements is dramatic, see Table 1.1. This shows a dismal picture indeed when one considers the social, economic and, above all, taste pressure which encourages the milling of rice. The reasons for the dramatic fall in nutritional value after milling are as follows: The starch is found principally in the endosperm; the lipids, fibres, vitamins and minerals are concentrated in the cellulose layer. Glucose molecules are found in two forms; amylase and amylopectine, the proportion varying between varieties. Most current varieties contain 12 – 35% amylase, the rest being amylopectine. Glutinous rice is low in amylase and tends to stick together in cooking. Simple sugars such as sucrose are present in brown rice in the 0,6 – 1,4% range, and in white rice from 0,3 – 0,5%. Fibre is present in the shell of brown rice but hardly at all anywhere else and therefore only marginally in white rice. Proteins, the second major constituent of rice, are present in the endosperm in the form of 1 - 3µm granules but these are eliminated in the milling process. Of 17.600 varieties of rice analysed by the IRRI, the percentage of protein varied from 4,3 to 18,2% with a middle point of 9,5%. Table 1.2 shows the amino acid content of the different forms and elements of IR-8.

Table 1.1 - Effect of refining and parboiling on rice, 100 g. The following table shows the outcome of damage as a percentage of roll weight with an assumed core diameter of 10 cm:

Brown rice White rice Parboiled rice
Energy, Kcal 360 365 370