Physicochemical and nutritional properties of rice as affected by parboiling steaming time at atmospheric pressure and variety

To elucidate the effect of different parboiling steaming time on the physicochemical and nutritional quality of rice, four varieties, NERICA1, NERICA7, IR841, and WITA4, were soaked at the same initial temperature (85°C) and steamed for 5, 15, 25, 35, and 45 min. NERICA7 steamed for 25 min recorded the highest head rice yield (71.9%). Nonparboiled IR841 recorded the shortest cooking time (17.0 min), while NERICA1 steamed for 35 min recorded the longest cooking time (26.1 min). NERICA1 steamed for 45 min was the hardest (63.2 N), while nonparboiled IR841 was the softest (28.7 N). NERICA7 recorded higher peak and final viscosities across all steaming times compared to the other varieties. NERICA7 steamed for 35 and 45 min recorded the lowest total starch (77.3%) and the highest protein (13.2%) content, respectively. NERICA7 steamed for 25 and 45 min recorded the highest phosphorus (0.166%), magnesium (572 mg/kg), and potassium (2290 mg/kg) content, respectively. We conclude that, depending on desired physicochemical and nutritional properties, specific varieties and steaming times can be selected to achieve those outcomes

Drivers of adoption and impacts of the improved GEM parboiling system for rice value chain upgrading on livelihood of women rice parboilers in Benin

Food insecurity and child malnutrition remain persistent problems in sub-Saharan Africa. Rice is a staple food for more than half of the world’s population. However, white rice is poor in micronutrients and records higher glycemic values compared to parboiled rice. An improved parboiling system called “Grain quality enhancer, Energy-efficient and durable Material” (GEM in short) allows the processing of quality rice with better physical and nutritional properties compared to traditional systems. This paper assessed the drivers and impact of the adoption of the GEM system on women’s livelihoods. A total of 822 rice women parboilers were randomly sampled and interviewed in Benin, in regions where the GEM system was introduced. We employed the endogenous switching regression model (ESR) to assess the impact of the GEM system. We found evidence that adoption of the GEM system increased women parboilers’ rice output rate (milling return), income and food security and reduced poverty. The impact of the GEM system is estimated at 14.4 kg of milled rice per 100 kg of paddy (21%), equivalent to US$ 7.3 of additional income (18%). A significantly lower poverty rate of 26% was found among households due to the adoption of the GEM system. These results are supported by women’s perceptions that the output rate, better nutritional value and reduction of broken rice during milling are major advantages of the improved parboiling system. Policy actions such as training of local fabricators and credit options are required for out-scaling and sustainability of the improved parboiling system

Appropriate parboiling steaming time at atmospheric pressure and variety to produce rice with weak digestive properties

Consumers with diabetes mellitus have shown interest in products with low postprandial glucose. To produce rice for this group of consumers, the effect of parboiling steaming time (0, 5, 15, 25, 35, and 45 min) and variety (NERICA1, NERICA7, WITA4, and IR841) on resistant, damaged starch fractions and glycemic response in rats was investigated. Resistant and damaged starch fractions were influenced by variety and steaming time but this was not the case for glycemic index. Nonparboiled NERICA7 and NERICA7 steamed for 25 min recorded the highest (10.07%) and lowest (2.49%) resistant starch fraction, respectively. Resistant starch correlated negatively with protein and sodium and positively with lipids. Damaged starch was high for WITA4 steamed for 45 min (26.80%) and low for nonparboiled NERICA1 (6.59%). Damaged starch correlated positively with lipid content and negatively with ash and total starch content. NERICA7 steamed for 35 min recorded the lowest postprandial glucose level 30 min after feeding (0.16 g/L), while WITA4 steamed for 15, 25, and 35 min and nonparboiled NERICA7 recorded higher levels (0.76, 0.91, 0.84, and 0.76 g/L, respectively). NERICA7 steamed for 35 min recorded both low glycemic and weak digestive properties because the glycemic index was lowest 120 min and increased steadily up to 180 min after feeding. We conclude that the digestive properties of rice depend both on the intrinsic properties of the variety and the parboiling steaming time

Hedonic Pricing of Rice Attributes, Market Sorting, and Gains from Quality Improvement in the Beninese Market

Latent class analysis is applied to a hedonic price model to examine the presence of heterogeneity in consumer valuation of quality attributes in the Beninese rice market. Three classes of consumers are found in proportions of 5, 56, and 39 percent. We employ a partial equilibrium model and find modest gains in consumer surplus from an increase in head rice and reduction in chalkiness. The results provide evidence of market sorting, which should be taken into consideration in upgrading rice value chains. Also, it is important to assess potential gains from quality improvement to determine priorities for research and development

Postharvest Adaptation Strategies to the Effects of Temperature Variations and Farmer-Miller Practices on the Physical Quality of Rice in Cameroon

In order to develop simple and adaptable measures to reduce the impact of changing climatic con ditions and poor postharvest practices on grain quality, data on temperature and postharvest practices were collected and correlated with physical grain quality parameters for 3 rice devel opment hubs (Ndop, Lagdo and Mbam) in Cameroon. Inter-annual variations in temperature and thermal amplitudes were the highest in Ndop followed by Mbam and the least in Lagdo. When the same rice variety was grown in the hubs and milled with a laboratory hand dehusker, the mean chalky score was highest in Ndop (18%) and least in Mbam (11%). In addition, Ndop recorded higher grain fissures and broken fractions compared to Mbam or Lagdo. Positive correlations were observed between thermal amplitudes, grain fissures and the proportion of broken fractions. However, rice milled using commercial mills located in the hubs recorded the highest broken frac tions in Mbam (54% - 63%), followed by Lagdo (43% - 52%) and the least in Ndop (35% - 38%). The type of mills in the hubs was responsible for these differences as Mbam had only Engelberg types mills that recorded higher broken fractions than in Ndop where only rubber roll mills were present (P < 0.05). Lagdo had a mixture of Engelberg and rubber roll mills and recorded interme diate broken fractions. Proper parboiling, recovery and processing of poorly filled and immature grains during parboiling and processing of low-grade and fine broken rice into product generally accepted by the local population were demonstrated as simple adaptation strategies to mitigatethe adverse effects of changing climatic conditions and poor postharvest practices on the physical quality of rice especially in sub-Saharan African countries

Climate smart rice innovations to reduce the impact of climate change on the livelihood of value chain actors

Introduction Rice is a major source of nutrients, largely contributing to the food and nutrition security for millions of people in Africa although most countries still rely on huge imports to meet local demand. Extreme temperatures, drought, flooding, and high salinity are climate change related stresses that negatively affect rice yield and grain quality. Thus, tackling these constraints is a critical action to increasing rice self sufficiency in Cameroon and Africa in general. Methods The Africa Rice Center in partnership with the National Agricultural Research and Extension Services of its 28 member States operating within the framework of the Africa-wide Taskforces has developed, tested, validated, and are deploying breeding, agronomic and post-harvest approaches to mitigate the negative impacts of climate change on rice yield and quality in Africa. Results Breeding approaches have led to the development of drought, cold, submergence, stagnation flood, salinity, and anaerobic germination tolerant varieties that are also resistant or tolerant to biotic stresses. These have demonstrated better yields and grain quality under stressed conditions compared to counterparts lacking those specific traits. The system of rice intensification and alternate wetting and drying, mid-season drainage, smart-valleys approach for inland development, solar-powered irrigation system, no-till and rice straw mulching are agronomic approaches developed and these approaches have demonstrated significant increase in yield and grain quality compared to alternative approached under climate change stress conditions. Post-harvest approaches have focused on reducing grain breakages, chalkiness, mycotoxin contamination, insecticide and fungicide use, deforestation and value addition to broken rice and rice milling byproducts using environmentally friendly methods. Post-harvest innovations here include using improved rice parboiling fueled by rice husk, solar-powered hermetic storage systems, processing of fine broken rice into flour for porridges and bakery products and use of rice husk fan-assisted stoves for household cooking and the cottage processing industry. Conclusions and recommendations Although climate change is a serious threat to rice production affecting both yield and quality, African governments will have to implement policy measures that enhance the scaling and adoption of climate smart rice innovation developed by AfricaRice to mitigate the impact of climate change if they aspire to reduce rice imports

Valuation of rice postharvest losses in Sub-Saharan Africa and its mitigation strategies

Data on rice harvest and postharvest loss in Sub-Sahara Africa (SSA) is scanty making it difficult for stakeholders to appreciate the loss and set priority areas for loss reduction along the value chain. To address this problem, a protocol was developed and validated for postharvest loss (PHL) quantification in SSA. Quantitative losses at each segment were determined by field measurements. Interactive effect of origin of rice (domestic versus imported) and type of processing (white versus parboiled milled) on rice price in 33 markets in Africa was used to estimate qualitative loss for both white and parboiled milled rice. Total PHL for rice in SSA in 2018 is estimated at about US$ 10.24 billion, representing 47.63% of the expected total production. The highest loss recorded was quantitative loss before and during harvesting, followed by qualitative loss along the entire value chain, quantitative loss during milling, parboiling, threshing in that order, with the lowest being quantitative loss during drying. Priority areas to be targeted for PHL reduction in SSA and some loss mitigation tools and technologies piloted or suitable for SSA are proposed