Temperature and Maturity Stages Affect Anthocyanin Development and Phenolic and Sugar Content of Purple-Pericarp Supersweet Sweetcorn during Storage

Abstract

Purple-pericarp sweetcorn (PPS) is a novel product, requiring both purple pigment development and maintenance of sweetness. Storage period and temperature had a profound impact on total anthocyanin accumulation (TAC) and sugar content. While TAC remained relatively unchanged during 14-day storage at 4 °C, the first recorded observation of continuing accumulation of anthocyanin and phenolic compounds was concurrent with an increase in purple pigment coverage across the surface of the kernel at 23 °C. TAC in PPS significantly increased, doubling after 14 days at 23 °C. Anthocyanin concentration and kernel coverage were also affected by harvest maturity. The results indicated that biosynthesis of anthocyanins is still occurring during postharvest storage of PPS. A significant decline in sugar concentration was also observed during storage with a greater decline at 23 °C. As anthocyanin accumulation and maintaining sweetness are important factors for sweetcorn, identifying storage temperatures that optimize both quality criteria are required.

BREAKING THE TIGHT GENETIC LINKAGE BETWEEN THEa1ANDsh2GENES LED TO THE DEVELOPMENT OF ANTHOCYANIN-RICH PURPLE-PERICARP SUPER-SWEETCORN

“…Interestingly, sucrose concentration was not significantly different, and, as this constituted the main sugar present, also explain why total sugar concentration was also not significantly different between these lines. The principal sugar was identified as sucrose in both the parents and the progeny, which is in agreement with earlier studies based on brittle1 and sugary1 sweetcorn varieties (Hong et al, 2021; Vries and Tracy, 2016).…”

“…As pericarp tissue is maternal, the pericarp of all kernels on a single cob shares the same genotype as the mother plant. As such, the colour differences most likely came from underlying variation in aleurone colour, as absence of colour in the aleurone will make the overlying pericarp above look less purple, especially at sweetcorn eating stage, when anthocyanin is still accumulating (Hong et al, 2021). The reason behind this may be partly due to the absence or presence of aleurone pigmentation, but could also be due to inter-kernel differences in aleurone anthocyanin profile.…”

“…Anthocyanins were extracted from the frozen powder sample (~1 g) following the method of Hong et al, (2020b). The anthocyanin analysis was determined using an ultra-high performance liquid chromatography-diode array detection-mass spectrometry (UHPLC-DAD-MS, Shimadzu, Kyoto, Japan) following the method of Hong et al, (2021).…”

“…Sugar extraction of 23 DAP kernels was carried out as reported previously by Hong et al, (2021). Briefly, frozen powdered samples (0.5 g) were homogenized with 10 mL of aqueous methanol (70%).…”

Profiling and Quantification of Anthocyanins in Novel Purple-Pericarp Sweetcorn and Purple-Pericarp Maize

“…Anthocyanin profiles were obtained using UHPLC-DAD-MS (ultra-high performance liquid chromatography–diode array detection-mass spectrometry) (Shimadzu, Kyoto, Japan) as described previously by Hong et al, (2021). For operation of the instrument and data-processing LCMS software (Lab solutions) (Ver.5.85; Shimadzu) was used.…”