Effects of Waterlogging at Flowering Stage on the Grain Yield and Starch Quality of Waxy Maize

Waterlogging is a common abiotic stress in global maize production. Maize flowering stage (from tasseling to silking) is more fragile to environmental stresses, and this stage frequently overlapped the plum rain season in the middle and lower reaches of Yangtze river in China and affect the yield and quality of spring-sown maize severely. In the present study, the soil moisture content under control and waterlogging conditions at the flowering stage was controlled by a negative-pressure water supply and controlling pot device in a pot trial in 2014-2015. The grain yield, starch content, and starch structural and functional properties under two soil moisture levels were compared using Suyunuo5 (SYN5) and Yunuo7 (YN7) as materials, which are the control hybrids of National waxy maize hybrid regional trials in Southern China. The results observed that the grain yield was reduced by 29.1% for SYN5 with waterlogging due to the decreased grain weight and numbers, which was significantly higher than that of YN7 (14.7%), indicated that YN7 was more tolerant to waterlogging. The grain starch content in YN7 was decreased by 9.4% when plants suffered waterlogging at the flowering stage, whereas the content in SYN5 was only decreased in 2014 and unaffected in 2015. The size of starch granules and proportion of small-molecule amylopectin with waterlogging at the flowering stage increased in SYN5 and decreased in YN7 in both years. The type of starch crystalline structure was not changed by waterlogging, whereas the relative crystallinity was reduced in SYN5 and increased in YN7. The pasting viscosities were decreased, and the pasting temperature was unaffected by waterlogging in general. The gelatinization enthalpy was unaffected by waterlogging in both hybrids in both years, whereas the retrogradation enthalpy and percentage in both hybrids were reduced by waterlogging in 2014 and unaffected in 2015. Between the two hybrids, YN7 has high pasting viscosities and low retrogradation percentage than SYN5, indicated its advantages on produce starch for more viscous and less retrograde food. In conclusion, waterlogging at the flowering stage reduced the grain yield, restricted starch accumulation, and deteriorated the pasting viscosity of waxy maize. Results provide information for utilization of waxy maize grain in food production.

The Effects of Genotype × Environment on Physicochemical and Sensory Properties and Differences of Volatile Organic Compounds of Three Rice Types (Oryza sativa L.)

Understanding the effects of genotype, environment and their interactions on rice quality is of great importance for rice breeding and cultivation. In this study, six rice varieties with two indica, two japonica and two indica-japonica types of rice were selected and planted at ten locations in Zhejiang Province to investigate the genotype (G) × environment (E) on physicochemical and sensory properties and the differences of volatile organic compounds (VOCs) among the three types of rice. Analysis of variances showed that apparent amylose content (AC), total protein content (PC), alkali spreading value (ASV), RVA profiles, and appearance (ACR), palatability (PCR), and sensory evaluation value (SEV) of cooked rice and texture of cooled cooked rice (TCCR) were mainly affected by genotypic variation, whereas the smell of cooked rice (SCR) was mainly affected by environment (p < 0.05). The G × E effect was significant for most parameters. The weather in the middle and late periods of filling had important effects on the formation of rice quality, especially on setback (SB) and pasting temperature (PT) (p < 0.01). They were negatively correlated with the texture of cooked rice (TCR) and SEV (p < 0.05). Peak viscosity (PV) and breakdown (BD) were positively related to the sensory evaluation parameters (p < 0.01) and could be used to predict cooked rice quality. A total of 59 VOCs were detected, and indica, japonica and indica-japonica had 9, 6 and 19 characteristic compounds, respectively. The principal component analysis showed that the physicochemical and sensory properties and VOCs of indica-japonica rice were more stable than those of indica and japonica rice at ten locations in Zhejiang Province. It is helpful for rice breeders to understand how the environment affects the physicochemical, sensory properties and VOCs of the three rice types, and it is also important for food enterprises to provide rice products with stable quality.

Starch Physicochemical Properties of Normal Maize under Different Fertilization Modes

Improving the quality with desired functions of natural starch through agronomic practice will meet the increasing need of people for natural, functional foods. A one-off application of slow-release fertilizer is a simple and efficient practice in maize production, though its influence on the starch quality is scarce. In the present study, the structural and functional properties of the starch of normal maize under two fertilization modes (one-off application of slow-release fertilizer at the sowing time (SF), and three applications of conventional fertilizer at the sowing time, and topdressing at the jointing and flowering stages (CF)) under the same fertilization level (N/P₂O₅/K₂O = 405/135/135 kg/ha) were studied using Jiangyu877 (JY877) and Suyu30 (SY30) as materials. The observed results indicate that the size of starch granules was enlarged by fertilization and the size was the largest under CF in both hybrids. The amylose content was unaffected by CF and reduced by SF in both hybrids. In comparison to no fertilizer (0F), the peak 1/peak 2 ratio was decreased by CF in both hybrids, whereas the ratio under SF was unaffected in JY877 and decreased in SY30. The amylopectin average chain-length was reduced by fertilization and the reduction was higher under CF in JY877. The relative crystallinity was increased by CF in both hybrids and the value under SF was unaffected in SY30 and increased in JY877. The peak, trough, and final viscosities of starch were increased by fertilization in both hybrids. The starch thermal characteristics in response to fertilization modes were dependent on hybrids. The retrogradation enthalpy and percentage were increased by CF in both hybrids, whereas those two parameters under SF were increased in SY30 and decreased in JY877. In conclusion, starch with similar granule size, higher peak 1/peak 2 ratio, and lower relative crystallinity was obtained under SF than under CF for both hybrids. Longer amylopectin chain-length was observed in JY877, which induced lower pasting viscosities in SY30 and lower retrogradation characteristics in JY877.

Water and heat stresses during grain formation affect the physicochemical properties of waxy maize starch

BACKGROUND

Maize is frequently subjected to simultaneous water (drought or waterlogging) and heat (HS) stresses during grain formation in southern China. This work examined the effect of high temperature combined with drought (HD) or waterlogging (HW) during grain formation on the starch physicochemical properties of two waxy maize hybrids, namely Suyunnuo5 (SYN5) and Yunuo7 (YN7).

RESULTS

Heat stress enlarged the starch granule size, and water stresses aggravated this effect. Heat stress reduced the ratio of small molecular weight fractions for both hybrids, and HD aggravated this reduction only in SYN5. Relative crystallinity in SYN5 was increased by stresses but in YN7 it was unaffected by HD, reduced by HS, and increased by HW. Fourier-transform infrared (FTIR) spectrometry results showed that the 1045/1022 cm^-1 ratio in SYN5 was not influenced by HW but was increased by other stresses, and that in YN7 it was increased by all stresses, with the highest value induced by HW. Peak viscosity was decreased, whereas gelatinization temperatures and retrogradation percentage were increased by all of these stresses. These effects were exacerbated by combined heat and water stresses. The maximum decomposition rate was severely increased by HW.

CONCLUSION

Drought or waterlogging at grain formation stage aggravated the detrimental effects of HS on the starch physicochemical properties of waxy maize. © 2020 Society of Chemical Industry.

Application of Exogenous Phytohormones at Silking Stage Improve Grain Quality under Post-Silking Drought Stress in Waxy Maize

The application of exogenous plant growth regulator can improve plant resistance to drought stress. The effects of application of exogenous cytokinin (CTK), brassinolide (BR), or gibberellic acid (GA) at the silking time on the grain quality of two waxy maize hybrids under drought stress at grain formation stage were studied. Grain weight of both hybrids was unaffected by exogenous phytohormones under control conditions but increased under drought conditions with the application of BR. The grain starch content in response to drought varied with hybrid and phytohormone. Starch granule size and protein content in grains were increased by drought under all conditions, but various phytohormones exerted different forms of influence. The starch λ_max in Yunuo7 was unaffected by single or interaction of phytohormones and water deficit, λ_max in Jingkenuo2000 with BR was unaffected but with CTK or GA increased by drought. Relative crystallinity was reduced by drought without the application of phytohormone, but with phytohormones in response to drought it was different. Flour peak viscosity was reduced by drought. The value was increased with BR spraying under control and drought conditions. Retrogradation percentage under drought conditions was unaffected by exogenous phytohormones in Jingkenuo2000. In Yunuo7, retrogradation percentage was unaffected by BR but reduced by CTK and GA. In conclusion, spraying phytohormones at the silking stage can affect grain weight and starch quality, grains with a sticky taste can be improved by applying BR, and grains with low retrograde tendency can be produced by applying CTK.

Development of a dehydrated fortified food base from fermented milk and parboiled wheat, and comparison of its composition and reconstitution behavior with those of commercial dried dairy-cereal blends

Dehydrated blends of milk and cereal are reconstituted and consumed as a nutritious soup or porridge in many regions; the composition and reconstitution behavior of the blends are likely to impact on nutritional quality and consumer acceptability of the soup/porridge. Experimental samples of dried fermented milk-bulgur wheat blend (FMBW) and commercial samples of dried dairy-cereal blends, namely kishk, tarhana, and super cereal plus corn-soy blend (SCpCSB) were compared for composition, color, water sorption, and reconstitution characteristics. FMBW blends had higher contents of protein, Ca, lactose and lactic acid, lower levels of salt (NaCl) and Fe, and a lighter, more-yellow color (higher L* and b*-color co-ordinates) than tarhana or kishk. Compared with SCpCSB, FMBW had numerically higher levels of protein, lactose, and lactic acid, lower levels of Ca, Fe, Zn, and Mg, and lower pH. Tarhana had highest mean levels of starch, and on reconstitution (133 g/kg) had highest water holding capacity, viscosity during pasting and cooling, yield stress (σ 0), consistency coefficient (K), and viscosity on shearing from 20 to 120 s-1 at 60°C. Reconstituted FMBW, kishk, and SCpCSB had similar pasting and flow behavior properties. Overall, the composition (starch, protein, Ca, Mg), pasting and flow behavior characteristics of FMBW were closer to those SCpCSB and kishk than to tarhana. The results suggest that the FMBW powder, on appropriate supplementation with Ca, Fe, Zn and Mg, could be used for the development of customized fortified blended foods for specific groups.

Cereal type significantly affects the composition and reconstitution characteristics of dried fermented milk-cereal composites

BACKGROUND

Dairy and cereal products are frequently combined to create composites with enhanced nutritional benefits. Commercially available dried dairy-cereal composites are typically reconstituted and cooked to produce porridge or soup.

RESULTS

Dried fermented milk-cereal composites (FMCC) with ∼193 g kg^-1 protein were prepared by blending fermented milk with parboiled oats (FMCCo), wheat (FMCCw), or barley (FMCCb), incubating the blend, drying, and milling. Cereal type significantly affected the composition of the FMCC and the properties of the reconstituted, cooked FMCC (R-FMCC). The FMCCo had a higher starch and fat content and lower levels of lactose, lactic acid, and amylose than FMCCb. The R-FMCCo had higher viscosity during cooking at 95 °C and cooling to 35 °C, and higher values of yield stress (σ₀ ), consistency index (K) and viscosity on shearing from 20 to 120 s^-1 at 60 °C than R-FMCCb. The FMCCw had lower levels of fat and β-glucan than FMCCo or FMCCb, but was otherwise closer to FMMCb with respect to composition, cooking properties and flow behavior.

CONCLUSION

Differences in composition and consistency associated with cereal type are likely to affect the nutritional value of the FMCC. © 2018 Society of Chemical Industry.