The grain quality evaluation study under Project 1 shows that of the 32 Direct Seeded General Yield Trial (DSR-GYT) entries from 2014WS, 26 showed good milling recovery, were tall and slender and had average amylose content (AC), which indicates that the samples are soft to very tender during cooking. Most of the 72 Long Term Organic Fertilizer (LTOF) samples evaluated met the milling potential standard, with the exception of two (2) samples. Half of the aromatic entries had a very good grain quality score with high milling recovery; and AC were low to medium and thus expected to have tender cooked rice grains.
Preliminary findings of the study on Visible-Near-Infrared Spectroscopy for Rapid Assessment of Grain Quality of Philippine Rice showed that analysis and modeling of the entire sample set showed good prediction models for crude protein. The ultimate goal of the GQ project is to improve breeding efficiency for grain quality, ensure availability of cooked rice with longer shelf life for consumers, and develop milled rice prediction models for rapid analysis of grain quality. For Study 1, it covers GQ evaluation of rice lines before they are raised in the pre-stages of the National Cooperative Test (NCT) to select promising entries to speed up the screening, thereby reducing costs and maximizing resources.
Most of the samples were long and lean and had an Intermediate amylose content (AC), indicating that the samples are soft to very soft when cooked. Out of the 24 Direct Seeded Preliminary Yield Trial (DSR-PYT) samples, all 24 had excellent milling recovery except for PR41225-6-1-B-B. Most of the specimens were tall and lean and had Low to Intermediate AC, indicating that these specimens had good eating quality.
Twenty-eight samples had a good grain quality score, while the remaining eight (8) samples had poor grain quality with high chalky grains and high amylose content. Of the 59 Rainfed Elite Lines evaluated, most samples have excellent grain quality with high milling yield, medium and medium to long and lean grains. Most of the samples had intermediate AC and are therefore expected to have soft cooked rice grains.
Out of the 77 irrigated lowland – Ultra Early Maturing lines evaluated, 47 samples had excellent grain quality with high milling recovery, low amount of calcareous grains and with low to intermediate AC, indicating that these samples have tender cooked rice. Eleven (11) samples with very good grain quality have a low percentage of calcareous grains, low to medium. Aromatic rice samples had low to medium AC, and are therefore expected to have tender cooked rice grains.
Only two of the 14 Preliminary Yield Trial (PYT-R) entries had very good grain quality meeting milling potential standards, with class 1 to class 2 chalky grains and low to medium AC. The results of the study will not only provide valuable information on possible causes of cooked rice spoilage and its prevention, but also have the potential to save lives of the rice-consuming public. Preliminary analysis and modeling of the entire sample set showed good prediction models for crude protein (Table 6 and Figure 1).
Scatterplots for prediction models for Crude Protein at a 950-1650 wavelength range of the four forms of rice.
Nutrition, Health, and Wellness Potential of Philippine Rice and Rice-Based Crops
In raw form, the highest TPC on a fresh weight basis was: jute>chili (Mountain Province)>oyster mushroom>spinach>taro tuber. Chili had the highest TPC on a fresh weight basis (268.90 mg GAE/100 g) among the cooked samples analyzed, followed by jute, peas (Sumilang), water spinach and beans. Studies show that cooking, especially boiling or blanching, significantly reduces the phenolic content of rice-based crops (Azizah et al., 2009, Sultana et al., 2007, Kettawan et al., 2011) due to the breakdown of antioxidants, leaching into cooking water, oxidation by polyphenol oxidase and isomerization (Ahmed and Ali, 2013, Takenaka et al., 2006).
Heat processing generally causes degradation in food components, including phenolics, as observed in sweet potato (Padda and Picha, 2008), brassica vegetables (Sikora et al., 2012) and legumes (Xu and Chang, 2008, Barroga et al. 1985). The antioxidant capacity of the hydrophilic extracts was evaluated using the DPPH radical scavenging activity assay. The five rice-based crude crops exhibiting the highest DPPH radical scavenging activity among the samples, expressed on a fresh weight basis, were jute, taro (tuber), water spinach, chili pepper, and spinach.
Dry weight antioxidant capacities were highest in the following samples: jute>eggplant>water spinach>taro (tuber)>okra. In general, the antioxidant capacities decreased after heat processing, similar to those reported by other researchers (Kettawan et al., 2011, Tanongkankit et al., 2010, Oboh, 2005, Yamaguchi et al., 2001). On the contrary, improvement in antioxidant capacities was observed especially in sweet potato and chili pepper.
The TPC of the analyzed samples generally corresponded to their DPPH radical scavenging activities, as shown by the positive correlations, especially in crude forms (r=0.95, FW;. Mean values in the same column with the same letter are not significantly different at p = 0.05 FFP – farmer's fertilizer practice FFS – farmer's field school FGD – focus group discussion FI – farmer's innovator.
NCT – National Cooperative Testing NFA – National Food Authority NGO – non-governmental organization NE – natural enemies. RQCS – Rice Quality Classification Software RS4D – Rice Science for Development RSO – Rice Sufficiency Officer RFL – Rainfed Lowland RTV – Rice Tungrovirus.
