Effects of Drain and Harvest Dates on Rice Sensory and Physicochemical Properties

Abstract

Timing of field draining and harvesting of rice with meteorological conditions can allow growers to foster conditions for high head rice yield (HRY). The effects of timing of draining and harvesting on rice sensory and physicochemical properties are not well understood. The objective of this study was to determine the effects of varying drain and harvest dates on the sensory and physicochemical properties of M‐202 grown in California under controlled field conditions. Drain date had a significant (P < 0.05), but very small, effect on amylose and protein contents, with amylose being highest at the late drain date and protein being the lowest at the early drain date. Breakdown and setback were lowest for early and normal drain dates, respectively; however, no significant (P > 0.05) differences in texture were measured as a result of these parameters being low. Drain date did not affect the volatile composition or flavor of the rice. Harvest date had no effect (P > 0.05) on amylose content and a significant (P < 0.05), but very small, effect on protein content. Harvesting at the earliest date (9/30) resulted in rice with higher setback and lower breakdown than at the last date (10/16) and, subsequently, the early harvested rice, when cooked, was harder, more cohesive, and absorbed less saliva in the mouth. However, the differences in texture measured by the panelists were very small and would possibly not be noticed by untrained palates. The lowest levels of the lipid oxidation products 1‐pentanol, hexanal, and nonanal occurred in rice with the lowest harvest moisture content (HMC): rice harvested on 10/13 and 10/16. Differences in levels of lipid oxidation products and branched chain hydrocarbons did not lead to significant (P > 0.05) differences in flavor. In summary, M‐202 demonstrated stable composition, physicochemical properties, flavor, and texture across drain and harvest dates.

Rice Aroma and Flavor: A Literature Review

“…M-202 and Akitakomachi) harvested at differing moisture contents and immediately dried or held for 48 hr before drying (Champagne et al 2005). Microbes found on the freshly harvested rice grow under these conditions and may produce volatile compounds that affect the flavor or aroma of the white rice obtained after drying and milling.…”

Analysis of flavor volatiles of glutinous rice during cooking by combined gas chromatography–mass spectrometry with modified headspace solid-phase microextraction method

“…This technique was introduced in studies on the flavor indicators of rice (Grimm et al, 2001(Grimm et al, , 2004Wongpornchai et al, 2004). Champagne et al (2004Champagne et al ( , 2005 investigated the volatile microbial metabolites gathered in rice based on the SPME technique. Laguerre et al (2007) reported the rapid evaluation of rice aroma by analysis of the volatile fraction using SPME directly coupled with mass spectrometry (MS).…”

Exogenous application of mixed micro-nutrients improves yield, quality, and 2-acetyl-1-pyrroline contents in fragrant rice

“…Thai 'jasmine' and Pak-Indian 'basmati' varieties are highly valued by consumers globally and gaining popularities in international markets (Huang et al, 2012), while the sale-price of aromatic rice is higher than non-aromatic rice (You et al, 2012). Through strumental analyses, it is well recognized that different volatile compounds involved in rice aroma formation (Champagne et al, 2005), of which 2-acetyl-1-pyrroline (2-AP) is a key aromatic compound Li et al, 2016). The organic compounds extracted from different fragrant rice cultivars showed similar aroma profile, nevertheless the levels of different aroma compounds varied significantly (Maraval et al, 2008).…”