24 research outputs found
Sequence stratigraphic analysis of the CRP-1, Cape Roberts Project, McMurdo Sound, Antarctica
Vertical facies associations within the CRP- 1 drillcorc reveal a strong cyclicity
and facilitate the development of a sequence stratigraphic framework. The sedimentary
record appears to be punctuated by a series of erosional sequence boundaries which are here
inferred to be the product of cycles of glacial advance and retreat. This is further supported
by the absence of thick (preglacial) progradational sequences within the drill core. Eight
Miocene and at least two Quaternary sequences are identified on the basis of facies and
textural association. The core is dominated by transgressive (local glacial retreat) and high
stand (local glacial minimum) deposits, with regressive (local glacial advance) and
lowstand (local glacial maximum) events being under represented
Pre-harvest curing: Effects on skin adhesion, chemical composition and shelf-life of sweetpotato roots under tropical conditions
Excoriation (skinning injury) is a serious post-harvest problem for sweetpotato roots. In industrialized countries, sweetpotatoes are exposed to post-harvest curing to facilitate skin toughening and wound healing. However, in developing regions, such a practice is barely undertaken. Pre-harvest curing (PHC), where sweetpotatoes are subjected to defoliation before harvest, is a potential alternative to post-harvest curing. A field trial was conducted in southern Ethiopia. Roots underwent PHC treatment for 3, 7, 10, and 14 days, with 0 days as a control sample. Skin adhesion and chemical composition (ash, crude fibre, crude protein, dry matter, and starch) of the parenchyma and the periderm were measured. Storage testing at ambient conditions for 30 days was conducted. Skin adhesion among all the treatments was significantly increased. The maximum skin adhesion was observed after 14 days (358.92 mN.m); however after 7 days of PHC, no significant change occurred. Root dry matter and ash content remained unaffected by the treatments. An increase in periderm crude fibre was observed for treatment samples, indicating lignification. Parenchyma crude protein concentration demonstrated a sudden drop in value from the control to 3 days of PHC (5.19 to 2.32%). For successive durations, crude protein started to increase from 3 days, demonstrating an active protein metabolism. Starch, the most important constituent affecting palatability and processing of sweetpotato, was not affected by PHC. Roots subjected to PHC for 10 and 14 days presented a potential for enhancing shelf life by having a significantly lower weight loss after 30 days of storage