Roma rice (Oryza sativa L., Italian variety “Roma”, Long A, pearled grain)

Description

Roma rice is a historic Italian variety of Oryza sativa L. belonging to the Long A commercial group and characterised by a large, long, pearled grain. It is a classic japonica-type rice of the Italian rice districts (Piedmont, Lombardy, Veneto, Emilia-Romagna, Sardinia), where it has been traditionally cultivated for decades and widely used in home and restaurant cooking.

The grain of Roma is fairly long, wide and semi-tapered, with a typical pearled endosperm: the central zone of the kernel is opaque (“pearl”), while the surrounding part is more translucent. This internal structure is associated with a relatively low amylose content and a high capacity to release starch during cooking, which favours the formation of creamy, cohesive preparations. Compared with very high-end risotto rices (such as Carnaroli), Roma tends to cook slightly faster and is sometimes considered less firm, but it compensates with good creaminess and practicality in everyday use.

Culinarily, Roma is appreciated for its ability to absorb condiments well and for its moderate stickiness, which makes it suitable for risotti, baked rice dishes, timbales and arancini. The combination of grain size, pearled structure and cooking behaviour positions Roma as a “workhorse” rice for many traditional Italian recipes that require a rice capable of binding sauces and fillings while maintaining a recognisable grain.

Botanical classification
Common name: Roma rice (Long A, pearled grain)
Clade: Angiosperms
Order: Poales
Family: Poaceae
Genus: Oryza
Species: Oryza sativa L.

Cultivation and growth conditions

Climate
Roma rice is an Italian Long A cultivar with a pearled grain, adapted to warm–temperate growing areas with hot summers and high water availability. It requires a growing season free from frost, with high temperatures during tillering, stem elongation and anthesis. The crop is sensitive to cold in the early stages and at flowering, which can reduce grain set and yield.

Exposure
Like other paddy rice types, it needs full sun to ensure good photosynthetic activity and correct panicle development. Under prolonged shading, growth is reduced, plants are weaker and productivity declines.

Soil
Roma rice is grown on flat soils suitable for flooding, preferably clay or clay–loam soils with good organic matter content and water-holding capacity. Very sandy, highly permeable soils are not recommended, as they do not allow a uniform water layer to be maintained. Optimal pH ranges from slightly acidic to neutral or mildly alkaline.

Irrigation
The crop is usually cultivated under flooded conditions, maintaining an even water layer over the soil for much of the vegetative cycle. Proper management of water levels in the different stages (pre-emergence, tillering, stem elongation, ripening) is essential to control weeds, prevent water stress and promote uniform growth. Sudden changes in water level or unplanned dry periods can compromise yield and quality.

Temperature
Optimal temperatures for germination are above 12–13 °C, while for vegetative growth and flowering ideal values are between 20 and 30 °C. Cold episodes during anthesis reduce fertilization and grain set. Conversely, prolonged heat combined with strong radiation and dry winds can cause grain scorching and quality defects (breakage, chalkiness).

Fertilization
Roma rice requires balanced fertilization with nitrogen (N), phosphorus (P) and potassium (K):

• Nitrogen, applied in split doses, promotes regular tillering without excessively increasing lodging risk;

• Phosphorus supports early root system development;

• Potassium contributes to lodging resistance and grain quality.

Excess nitrogen increases the risk of fungal diseases (such as blast), favours lodging and can compromise yield stability.

Crop care
Main agronomic practices include:

• weed control through crop rotation, possible false sowing, mechanical and/or selective chemical methods;

• accurate land levelling to ensure uniform flooding;

• careful regulation of water levels to limit unwanted aquatic weeds and reduce stress;

• monitoring of diseases (e.g. blast) and pests, applying integrated pest management strategies;

• adjustment of sowing density to limit internal competition and lodging risk.

Good air circulation within the canopy helps limit diseases and supports proper panicle formation.

Harvesting
Harvest takes place when grain ripening is uniform and grain moisture is suitable for mechanized combining. Excessive delays may lead to lodging, shattering and quality loss. After harvest, grain is dried to a moisture content appropriate for safe storage and subsequent processing.

Propagation
The Roma cultivar is propagated using certified seed, produced in varietal seed multiplication plots to ensure genetic purity, grain uniformity and stable technological and cooking characteristics. On farm, paddy sowing (broadcast or in rows, on dry soil or under water) is carried out by adjusting the seed rate according to the target plant density, soil fertility and the agronomic technique adopted.

Indicative nutritional values per 100 g
(white Roma rice, raw – typical for Italian pearled Long A rices)

• Energy: ~ 340–360 kcal

• Water: ~ 8–13 g

• Total carbohydrates: ~ 75–78 g

  • mostly starch

• Dietary fibre: ~ 0.5–2 g

• Protein: ~ 6–8 g

• Total fat: ~ 0.4–1.0 g

  • first occurrence SFA (Saturated Fatty Acids): small fraction of total fat; excessive dietary SFA intake is associated with increased LDL cholesterol and cardiovascular risk

  • MUFA (MonoUnsaturated Fatty Acids): present in small amounts

  • PUFA (PolyUnsaturated Fatty Acids): present in small amounts, generally comparable to or slightly above MUFA

Micronutrients include small amounts of B-group vitamins and minerals (phosphorus, magnesium, iron, zinc). As with most white rices, the removal of bran and germ during milling reduces fibre and micronutrient content compared with wholegrain rice.

Key constituents

• Complex carbohydrates (starch: amylose + amylopectin)

• Rice proteins in moderate amounts

• Very low total lipid content, made up of SFA, MUFA and PUFA in small absolute quantities

• Dietary fibre in low amounts in the milled grain

• Micronutrients (B vitamins and minerals) in modest concentrations

• Minor bioactive compounds mainly associated with the outer layers, which are largely removed in white Roma rice

Production process

1. Cultivation

   • sowing of Roma-type Long A japonica rice in flooded paddy fields

   • management of water, fertilisation, weed control and phytosanitary protection

   • growth and development until full grain maturity

2. Harvesting

   • mechanical harvesting of rough rice (paddy) at the appropriate moisture level

3. Drying

   • controlled drying of paddy to safe storage moisture

4. Cleaning

   • removal of foreign material (straw, stones, soil remnants, weed seeds)

5. Dehusking

   • removal of the husk to obtain brown Roma rice

6. Milling and polishing

   • removal of bran layers and light polishing to obtain white, pearled Roma Long A rice

7. Sorting and packaging

   • separation of broken grains and defects

   • packaging in bags or other containers for retail, catering or industrial use

Physical properties

• Grain type: Long A, large, long and semi-tapered

• Endosperm: pearled, with a central opaque area and less translucent surroundings

• Colour: white to ivory in the milled product

• Grain dimensions (typical Roma-type): length around 7 mm, relatively high width and robust cross-section

• Non-aromatic, non-glutinous rice

Sensory and technological properties

• Flavour: neutral, mild cereal taste, ideal for conveying the flavours of broths, sauces and fillings

• Aroma: non-aromatic (no jasmine/basmati-type fragrance)

Texture and cooking behaviour

• tends to cook in relatively short times compared with some other Long A rices

• releases a significant amount of surface starch, generating natural creaminess and light stickiness

• grains remain recognisable but tend to bind together, forming a cohesive structure in risottos, timbales and arancini

• good capacity to absorb condiments and sauces

Technologically, Roma is particularly suited to:

• risottos (especially home-style or less technically demanding ones)

• sauced rice dishes (rice with tomato sauces, ragù, etc.)

• baked rice, timbales and rice cakes

• preparations where rice is expected to help bind ingredients

Food uses

• everyday risottos, especially where convenience and creaminess are prioritised over very firm, al dente grains

• rice with sauce (tomato-based, meat-based, vegetable-based)

• baked dishes and timbales, including au gratin preparations

• arancini and croquettes, where the starch released by Roma helps hold the filling together

• thick soups and stews where rice contributes texture and body

Less suitable for:

• very dry, separate-grain dishes (for which Long B rices are generally preferred)

• recipes where extremely firm, well-separated grains with minimal stickiness are required over long holding times

Nutrition and health

Roma rice, like other refined Italian Long A rices, is a source of complex carbohydrates with moderate protein and very low fat content, and is naturally gluten-free.

Health-related considerations:

• due to milling, fibre content is relatively low; the glycaemic index is generally medium to medium-high, similar to other white rices

• the glycaemic impact depends on portion size, cooking degree and on the presence of vegetables, pulses, fats and proteins in the meal

• combining Roma rice with vegetables, legumes, lean proteins and quality fats improves the nutrient density of the dish and helps modulate the glycaemic response

Within a balanced dietary pattern and with appropriate portions, Roma can contribute effectively as a carbohydrate source, especially in traditional dishes where rice plays a structural and sensory role.

Portion note

Indicative dry Roma rice portions:

• as main carbohydrate component or first course: 70–80 g per person

• as side dish: 50–60 g per person

Portions should be adapted to age, body size, physical activity level and presence of other carbohydrate foods in the meal.

Allergens and intolerances

• Roma rice is naturally gluten-free, suitable for coeliac and gluten-sensitive individuals, provided that cross-contact with gluten-containing cereals is prevented in production and packaging

• true rice allergy is uncommon; Roma is generally well tolerated

• digestibility is usually good; any digestive issues are typically more related to the meal as a whole than to the rice itself

Storage and shelf-life

• store dry Roma rice in a cool, dry place, away from light and strong odours

• keep packs well closed, or transfer the rice into airtight containers after opening

• typical shelf-life of packaged white Roma rice is up to about 24 months, depending on packaging and storage conditions

• cooked rice should be cooled quickly, stored in the refrigerator and consumed preferably within 24 hours, observing good hygiene practices

Safety and regulatory aspects

• Roma rice is subject to general cereal and rice regulations regarding contaminants (e.g. pesticide residues, heavy metals, mycotoxins) and microbiological criteria

• must comply with legal requirements on labelling, traceability and hygiene

• any nutrition or health claims (e.g. “gluten-free”) must meet specific legal conditions and be supported by appropriate production and analytical controls

Labelling

On consumer packaging, Roma rice labelling typically includes:

• product name: e.g. “Roma rice” or “Riso Roma”

• commercial type: Long A, pearled grain

• country of origin/production

• net quantity

• best-before date and batch identification

• storage instructions

• nutrition declaration per 100 g (and sometimes per portion)

• cooking time and suggested uses (e.g. “ideal for risotti, baked rice, arancini”)

• any claims (e.g. “gluten-free”) only when all regulatory requirements are satisfied

Troubleshooting

In cooking

• Risotto not creamy enough

  • possible causes: insufficient stirring, too little starch release, limited use of fats during mantecatura

  • corrective actions: adjust toasting and gradual stock addition; increase mantecatura with butter and/or cheese; avoid excessive washing of rice before cooking

• Grains breaking or becoming mushy

  • possible causes: too much water, overly vigorous boiling, excessive cooking time

  • corrective actions: reduce water ratio, maintain a gentle simmer, check doneness earlier

• Rice too sticky for the intended dish

  • for preparations requiring more separation, reduce cooking time slightly, adjust water, or switch to a less pearled Long B variety

In storage

• Off-odours or stale notes

  • source: storage near strongly scented products or overly long storage

  • remedy: use airtight containers, store away from strong odours, rotate stock

• Presence of insects

  • linked to warm, humid conditions and long storage

  • remedy: discard infested product, clean storage area, and store in cool, dry, sealed conditions

Main INCI functions (cosmetics)

In cosmetics, rice-derived ingredients are indicated at species level as Oryza sativa, without specifying the variety (such as Roma). Typical rice-based INCI ingredients include:

• Oryza Sativa (Rice) Starch – used as an absorbent, opacifying and texturising agent in powders and skin-care products

• Oryza Sativa (Rice) Bran Oil – emollient and skin conditioning oil used in creams, lotions and hair-care formulations

• Oryza Sativa (Rice) Extract – used primarily for skin conditioning and to provide minor antioxidant and protective functions

Roma may serve as one of the possible agricultural sources for these ingredients, but it is not distinguished on cosmetic labels.

Conclusion

Roma rice is a classic Italian Long A, pearled-grain variety with a large, long and robust kernel that releases enough starch during cooking to produce creamy, cohesive preparations. Its practical cooking time, good capacity to absorb condiments and natural tendency towards creaminess make it particularly suitable for risottos, sauced rice dishes, baked rice, timbales and arancini.

From a nutritional standpoint, Roma behaves like other refined white rices: rich in complex carbohydrates, with moderate protein, very little fat and naturally gluten-free. When used in appropriate portions and combined with vegetables, pulses, lean proteins and quality fats, Roma can form part of balanced, flavourful meals while providing the textural and structural properties traditionally appreciated in Italian cuisine.

Mini-glossary

• Long A rice – commercial class including rices with long, relatively broad grains (compared with Long B), typical of many Italian table and risotto rices.

• Pearled grain – grain with a central opaque zone (“pearl”) in the endosperm, associated with specific starch distribution and enhanced starch release during cooking, which supports creaminess.

• Starch (complex carbohydrate) – main carbohydrate in rice, composed of amylose and amylopectin; responsible for energy supply and for many cooking and textural properties.

• Gluten-free – absence of gluten, the protein complex typical of wheat, barley and rye; all rice, including Roma, is naturally gluten-free.

• SFA – Saturated Fatty Acids; type of dietary fat which, in excessive amounts, is associated with increased LDL cholesterol and higher cardiovascular risk. In rice, SFA represent a very small proportion of a very low total fat content.

• MUFA – MonoUnsaturated Fatty Acids; unsaturated fats that can support a more favourable blood lipid profile when they replace part of SFA in the overall diet.

• PUFA – PolyUnsaturated Fatty Acids; include omega-6 and omega-3 fatty acids, involved in many physiological functions and considered beneficial when consumed in appropriate amounts and balance.

Studies

In general, rice contains more than 100 bioactive substances mainly in its bran layer including phytic acid, isovitexin, gamma-oryzanol, phytosterols, octacosanol, squalene, gamma-aminobutyric acid, tocopherol and derived from tocotrienol (1), antioxidants.

It does not contain beta carotene (provitamin A) and has a very low iron and zinc content (2).

In rice bran there are bioactive phytochemicals that exert protective actions against cancer that involve the metabolism of the host and the intestinal microbiome. A diet based on rice bran has shown positive effects in reducing the risk of colon cancer (3).

Rice studies

Allergies: Be careful, rice contains a certain amount of lactose.

The most common types of rice used are :

• Arborio : large grains,  the most common in Italy
• Ribe : elongated grains.
• Thaibonnet : medium, elongated and fine grains
• Rome : large grains
• Basmati : thin and elongated grains. Grown in Pakistan and India
• Carnaroli : large grains
• Vialone nano : large, round grains
• Original or Balilla : small round grains
• Jasmine : fine grains of Asian origin
• Red : red, small and narrow grains
• Wild : Zizania palustris
• Baldo : large, shiny grains
• Ganges : from India
• Footboard : releases a lot of starch
• Venus : from China and the Po Valley
• Patna : from Thailand. Long and narrow grains
• Sant'Andrea : Thick and long grains. Releases a lot of starch

Rice viruses and pests: Pseudomonas aeruginosa, Rice yellow mottle virus, Magnaporthe oryzae , Rice Tungro Bacilliform Virus , Lissorhoptrus oryzophilus Kuschel, Oebalus pugnax, Xanthomonas oryzae

References____________________________________________________________________

(1)  Bidlack W. Phytochemicals as bioacive agents. Lancaster, Basel, Switzerland: Technomic Publishing Co., Inc; 1999. pp. 25–36.

(2) Singh SP, Gruissem W, Bhullar NK.   Single genetic locus improvement of iron, zinc and β-carotene content in rice grains.    Sci Rep. 2017 Jul 31;7(1):6883. doi: 10.1038/s41598-017-07198-5.

Abstract. Nearly half of the world's population obtains its daily calories from rice grains, which lack or have insufficient levels of essential micronutrients. The deficiency of micronutrients vital for normal growth is a global health problem, and iron, zinc and vitamin A deficiencies are the most prevalent ones. We developed rice lines expressing Arabidopsis NICOTIANAMINE SYNTHASE 1 (AtNAS1), bean FERRITIN (PvFERRITIN), bacterial CAROTENE DESATURASE (CRTI) and maize PHYTOENE SYNTHASE (ZmPSY) in a single genetic locus in order to increase iron, zinc and β-carotene content in the rice endosperm. NAS catalyzes the synthesis of nicotianamine (NA), which is a precursor of deoxymugeneic acid (DMA) iron and zinc chelators, and also chelate iron and zinc for long distance transport. FERRITIN provides efficient storage of up to 4500 iron ions. PSY catalyzes the conversion of GGDP to phytoene, and CRTI performs the function of desaturases required for the synthesis of β-carotene from phytoene. All transgenic rice lines have significantly increased β-carotene, iron, and zinc content in the polished rice grains. Our results establish a proof-of-concept for multi-nutrient enrichment of rice grains from a single genetic locus, thus offering a sustainable and effective approach to address different micronutrient deficiencies at once.

(3) Zarei I, Oppel RC, Borresen EC, Brown RJ, Ryan EP. Modulation of plasma and urine metabolome in colorectal cancer survivors consuming rice bran.  Integr Food Nutr Metab. 2019 May;6(3). doi: 10.15761/IFNM.1000252.

Abstract. Rice bran has bioactive phytochemicals with cancer protective actions that involve metabolism by the host and the gut microbiome. Globally, colorectal cancer (CRC) is the third leading cause of cancer-related death and the increased incidence is largely attributed to poor dietary patterns, including low daily fiber intake. A dietary intervention trial was performed to investigate the impact of rice bran consumption on the plasma and urine metabolome of CRC survivors. Nineteen CRC survivors participated in a randomized-controlled trial that included consumption of heat-stabilized rice bran (30 g/day) or a control diet without rice bran for 4 weeks. A fasting plasma and first void of the morning urine sample were analyzed by non-targeted metabolomics using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). After 4 weeks of either rice bran or control diets, 12 plasma and 16 urine metabolites were significantly different between the groups (p≤0.05). Rice bran intake increased relative abundance of plasma mannose (1.373-fold) and beta-citrylglutamate (BCG) (1.593-fold), as well as increased urine N-formylphenylalanine (2.191-fold) and dehydroisoandrosterone sulfate (DHEA-S) (4.488-fold). Diet affected metabolites, such as benzoate, mannose, eicosapentaenoate (20:5n3) (EPA), and N-formylphenylalanine have been previously reported for cancer protection and were identified from the rice bran food metabolome. Nutritional metabolome changes following increased consumption of whole grains such as rice bran warrants continued investigation for colon cancer control and prevention attributes as dietary biomarkers for positive effects are needed to reduce high risk for colorectal cancer recurrence.

Brown DG, Borresen EC, Brown RJ, Ryan EP. Heat-stabilised rice bran consumption by colorectal cancer survivors modulates stool metabolite profiles and metabolic networks: a randomised controlled trial. Br J Nutr. 2017 May;117(9):1244-1256. doi: 10.1017/S0007114517001106. 

Abstract. Rice bran (RB) consumption has been shown to reduce colorectal cancer (CRC) growth in mice and modify the human stool microbiome. Changes in host and microbial metabolism induced by RB consumption was hypothesised to modulate the stool metabolite profile in favour of promoting gut health and inhibiting CRC growth. The objective was to integrate gut microbial metabolite profiles and identify metabolic pathway networks for CRC chemoprevention using non-targeted metabolomics. In all, nineteen CRC survivors participated in a parallel randomised controlled dietary intervention trial that included daily consumption of study-provided foods with heat-stabilised RB (30 g/d) or no additional ingredient (control). Stool samples were collected at baseline and 4 weeks and analysed using GC-MS and ultra-performance liquid chromatography-MS. Stool metabolomics revealed 93 significantly different metabolites in individuals consuming RB. A 264-fold increase in β-hydroxyisovaleroylcarnitine and 18-fold increase in β-hydroxyisovalerate exemplified changes in leucine, isoleucine and valine metabolism in the RB group. A total of thirty-nine stool metabolites were significantly different between RB and control groups, including increased hesperidin (28-fold) and narirutin (14-fold). Metabolic pathways impacted in the RB group over time included advanced glycation end products, steroids and bile acids. Fatty acid, leucine/valine and vitamin B6 metabolic pathways were increased in RB compared with control. There were 453 metabolites identified in the RB food metabolome, thirty-nine of which were identified in stool from RB consumers. RB consumption favourably modulated the stool metabolome of CRC survivors and these findings suggest the need for continued dietary CRC chemoprevention efforts.

Beyer P, Al-Babili S, Ye X, Lucca P, Schaub P, Welsch R, Potrykus I. Golden Rice: introducing the beta-carotene biosynthesis pathway into rice endosperm by genetic engineering to defeat vitamin A deficiency. J Nutr. 2002 Mar;132(3):506S-510S. doi: 10.1093/jn/132.3.506S. 

 Abstract. To obtain a functioning provitamin A (beta-carotene) biosynthetic pathway in rice endosperm, we introduced in a single, combined transformation effort the cDNA coding for phytoene synthase (psy) and lycopene beta-cyclase (beta-lcy) both from Narcissus pseudonarcissus and both under the control of the endosperm-specific glutelin promoter together with a bacterial phytoene desaturase (crtI, from Erwinia uredovora under constitutive 35S promoter control). This combination covers the requirements for beta-carotene synthesis and, as hoped, yellow beta-carotene-bearing rice endosperm was obtained in the T(0)-generation. Additional experiments revealed that the presence of beta-lcy was not necessary, because psy and crtI alone were able to drive beta-carotene synthesis as well as the formation of further downstream xanthophylls. Plausible explanations for this finding are that these downstream enzymes are constitutively expressed in rice endosperm or are induced by the transformation, e.g., by enzymatically formed products. Results using N. pseudonarcissus as a model system led to the development of a hypothesis, our present working model, that trans-lycopene or a trans-lycopene derivative acts as an inductor in a kind of feedback mechanism stimulating endogenous carotenogenic genes. Various institutional arrangements for disseminating Golden Rice to research institutes in developing countries also are discussed.