Ribe rice, long grain, lightly polished (Oryza sativa)

Description

Ribe rice is an Italian variety belonging to the group of long-grain rices, with medium–large kernels, elongated shape and slightly tapered cross-section. The term “lightly pearled” indicates that the grain has undergone a moderate degree of milling: part of the outer layers (bran and teguments) is removed, but to a lesser extent than in fully pearled rice. As a result, the grain shows a cream-white, slightly opaque colour, a surface that is less smooth than that of highly polished rice, and a structure that still retains a measurable amount of peripheral components.

From a technological standpoint, Ribe long-grain lightly pearled rice offers good cooking stability, with grains that tend to remain reasonably separate when properly hydrated, while developing some surface creaminess due to the available starch. The balance between milling level and residual outer fractions leads to medium cooking times (longer than fully pearled rice, shorter than wholegrain) and makes it suitable for dishes requiring structured grains without excessive firmness.

In compositional terms, compared with the fully pearled equivalent, lightly pearled Ribe retains a slightly higher amount of fibre, some minerals, and compounds associated with the outer parts of the grain, while behaving in the kitchen in a way similar to white rice. It is used in applications where a compromise is needed between grain integrity and the ability to bind seasonings: broths and soups, one-pot dishes, less “dry” rice salads, and everyday preparations in which a versatile starchy base with a neutral sensory profile is required, suitable for combining with a wide range of ingredients.

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

Cultivation and growth conditions

Climate
Ribe rice is an Italian Long type cultivar grown in warm–temperate areas, with hot summers and good water availability during the vegetative cycle. 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 flooded rice types, it needs full sun to ensure high photosynthetic performance and proper panicle development. Under shaded conditions, growth slows, the vegetative structure weakens and productivity declines.

Soil
Ribe rice is grown on flat soils suitable for flooding, preferably clay or clay–loam soils with good organic matter content and adequate water-holding capacity. Very sandy, highly permeable soils are unfavourable, as they do not allow a stable 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 a constant 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 ensure uniform growth. Sudden water-level fluctuations or unplanned dry periods reduce yield and grain quality.

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

Fertilization
Ribe rice requires balanced nutrition 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 improves lodging resistance and some grain quality parameters.

Excess nitrogen raises susceptibility to blast and other fungal diseases and favours lodging.

Crop care
Main agronomic practices include:

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

• accurate land levelling to ensure uniform flooding;

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

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

• choice of an appropriate sowing density to reduce internal competition and lodging risk.

Good air circulation within the canopy supports crop health and proper panicle formation.

Harvesting
Harvest takes place when grain ripening is uniform and grain moisture is suitable for combine harvesting. Excessive delay increases the risk of lodging, shattering and quality loss. After harvest, grain is dried to a moisture content suitable for safe storage and subsequent processing.

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

Indicative nutritional values per 100 g (raw product)

• Energy: 335–355 kcal

• Protein: 6.5–8.0 g

• Total fat: 0.8–1.2 g

  • SFA (Saturated Fatty Acids): very low

  • MUFA and PUFA: minor fractions

• Available carbohydrates: 76–79 g

  • Starch: predominant fraction

• Total fibre: 1.0–1.5 g

• Minerals: phosphorus, potassium, magnesium, manganese

• B-group vitamins: B1, B3, B6 in trace amounts

• Residual moisture: 11–14 %

Key constituents

• Starch granules mainly composed of:

  • amylose (relatively high share)

  • amylopectin

• Proteins with prevalence of prolamins and glutelins

• Dietary fibre (cellulose, hemicelluloses)

• Minerals: P, K, Mg, Mn

• Vitamins: B-complex in variable concentrations

• Lipid traces (triglycerides, minor phospholipid fractions)

Production process

1. Harvesting

   • Mechanical harvesting of the mature caryopsis.

2. Drying

   • Moisture reduction to levels suitable for safe storage.

3. Dehusking

   • Removal of the outer hull (husk).

4. Light polishing

   • Moderate abrasion with partial removal of the bran layers.

   • The “lightly polished” level corresponds to limited removal of outer tissues.

5. Sorting and cleaning

   • Calibration, removal of broken kernels and foreign matter.

6. Packaging

   • Dry atmosphere, often heat-sealed packs.

Physical properties

• Shape: elongated, regular long grains

• Colour: opaque off-white/cream

• Density: high, typical of semi-fine long-grain rice

• Water absorption: medium to high

• Starch gelatinisation: progressive and structurally stable

Sensory and technological properties

• Grains tend to remain well separated after cooking

• Limited surface stickiness

• Good ability to maintain internal structure and porosity

• Medium cooking times (about 15–18 minutes, depending on process and equipment)

• Good volume yield

• Neutral, mild flavour with light farinaceous notes

Food uses

• Side dishes with dry, separate grains

• Rice salads

• Baked dishes and timbales

• Stuffed preparations

• International dishes requiring distinct grains (e.g. some paella-style recipes, pilaf-style dishes)

Nutrition and health
The nutritional profile of Ribe rice, long grain, lightly polished is characterised by a predominance of complex carbohydrates and a very low fat content. The partial degree of refinement allows preservation of a modest amount of fibre and micronutrients compared with fully polished rice.

Proteins are present in moderate amounts and have a biological value lower than animal proteins but still contribute to the overall dietary protein intake. The low content of SFA supports its use in diets where limiting saturated fat is advisable.

From a glycaemic point of view, the relatively higher amylose fraction may favour a more gradual post-prandial glycaemic response compared with varieties richer in amylopectin, although rice as a whole remains a carbohydrate-rich food with a significant impact on blood glucose when consumed in large portions.

Portion note
A standard adult portion is generally in the range of 70–80 g of raw product, depending on total meal composition and energy needs.

Allergens and intolerances

• Naturally gluten free.

• May be subject to cross-contamination in facilities processing cereals containing gluten.

• No major specific allergens typical of rice are commonly reported, aside from rare individual sensitisation or rice-specific allergy.

Storage and shelf-life

• Store in a cool, dry place, away from moisture sources and direct sunlight.

• Typical shelf-life: 18–24 months after processing, under correct storage conditions.

• Recommended packaging: barrier bags, dry atmosphere, intact seals.

Safety and regulatory aspects

• Subject to legal limits for contaminants, pesticide residues and mycotoxins.

• Must comply with EU and national regulations concerning:

  • quality standards for rice

  • food hygiene and processing conditions

  • traceability across the supply chain

  • mandatory labelling (ingredient list, nutrition declaration, origin, etc.)

Labelling
Mandatory and standard information typically includes:

• sales name (e.g. “Ribe rice, long grain, lightly polished”)

• country of origin or place of provenance

• lot number and minimum durability date (“best before …”)

• nutrition declaration per 100 g (and, where applicable, per portion)

• storage instructions and basic directions for use/cooking

• any “gluten-free” claim only when supported by verified process controls and analytical checks

Troubleshooting

Possible defects and causes

• Excess broken grains:

  • excessive mechanical stress during processing

  • insufficient sorting and cleaning

• Excess stickiness after cooking:

  • absence of pre-rinsing to remove surface starch

  • cooking time longer than recommended or excessive water ratio

• Irregular cooking times within the same batch:

  • variable kernel moisture

  • mixture of different lots or harvest years

Prevention measures

• Gentle rinsing to reduce superficial starch, if compatible with the intended recipe

• Careful control of water/rice ratio and cooking time

• Proper storage to limit moisture gain or loss

• Use of homogeneous lots for industrial applications

Sustainability and supply chain

• Supply chain predominantly located in Italy, with cultivation mainly in the Po Valley (northern Italy).

• Possibility of full traceability from sowing to packaging, depending on the specific operator and certification schemes.

• Environmental impact influenced by:

  • water management practices in paddy fields

  • use of fertilisers and plant protection products

  • crop rotation and soil management strategies

• More sustainable approaches include:

  • rational irrigation and water-saving techniques

  • reduction and optimisation of agrochemical inputs

  • adoption of integrated or organic production systems where applicable

Main INCI functions (cosmetics)
When used in cosmetic formulations in derivative form (e.g. rice starch, rice powder, rice-derived extracts), this ingredient may perform several INCI functions, including:

• Absorbent (for sebum and moisture in powders and emulsions)

• Opacifying agent in face powders, foundations and similar products

• Skin conditioning agent, contributing to a smoother skin feel

• Viscosity controlling agent in some water-based or emulsion systems

Conclusion
Ribe rice, long grain, lightly polished is a technically versatile ingredient, offering good structural stability during cooking and a nutritional profile consistent with a starch-based staple food. The moderate processing level preserves part of the outer kernel tissues without compromising cooking performance. Overall, it is suitable for daily use in a wide range of savoury preparations, with high sensory acceptability and easy integration into varied and balanced diets, including gluten-free dietary patterns when cross-contamination is adequately controlled.

Mini-glossary

• SFA: Saturated Fatty Acids. A class of fats typically associated, when consumed in excess, with an increased cardiovascular risk. In this rice, the amount is very low.

• GMP/HACCP: Good Manufacturing Practices / Hazard Analysis and Critical Control Points. Systems and standards for managing hygiene, safety and quality in food production and processing.

• BOD/COD: Biochemical Oxygen Demand / Chemical Oxygen Demand. Indicators of the amount of organic and oxidisable substances in wastewater, used to evaluate the environmental impact of effluents from industrial processes, including food processing.

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.