Correlations among Quality Characteristics of Green Asparagus Affected by the Application Methods of Elevated CO₂ Combined with MA Packaging

Abstract

This research investigated the effects of continuous elevated CO₂ (20%, (v/v)) application or a 3 day CO₂ pretreatment followed by modified atmosphere (MA) or micro-perforated (MP) packaging on the postharvest quality of asparagus. The combination of CO₂ pretreatment with MA packaging (Pre-MA) inhibited the yellowing of asparagus and fresh weight loss (FWL), whereas stem firmness slightly increased with all elevated CO₂ treatments. CO₂ pretreatments increased antioxidant activity in the stem, but not in the tip, in contrast to the continuous flow CO₂ (Flow-CO₂) treatment. The phenolic and flavonoid contents increased in the elevated CO₂ pretreatments and Flow-CO₂ treatment. The elevated CO₂ treatments, especially Flow-CO₂, inhibited the development of microorganisms, and the treated asparagus did not decay. Pre-MA and Flow-CO₂ treatments were more effective in maintaining the visual quality and retarding the off-odor of asparagus. Furthermore, significant correlations between sensory quality characteristics and physiological-biochemical attributes were recognized; three principal components were extracted and they explained 86.4% of asparagus characteristics. The results confirmed the importance of visual quality, off-odor, firmness, color parameters, SSC and total phenolic content. In conclusion, elevated CO₂ pretreatment followed by MA packaging (Pre-MA) was beneficial for extending asparagus cold storage shelf life, and Flow-CO₂ was the best treatment for inhibiting postharvest decay.

Evaluation of the Storage Characteristics in Maintaining the Overall Quality of Whole and Fresh-Cut Romaine Lettuce during MA Storage

“…Putting whole romaine and fresh-cut romaine lettuce in gas-tight containers (1140 mL) and leaving it at room temperature (25 • C) for 3 h, carbon dioxide and ethylene gas were measured with an infrared sensor (Checkmate, PBI, Ringsted, Denmark) and gas chromatography (GC-2010, Shimadzu, Kyoto, Japan) to derive the respiration rate and ethylene generation rate. The concentrations of O 2 , CO 2 , and ethylene gas in the films were measured at 3 day intervals using GC and infrared sensors during storage [22]. The fresh weight loss is expressed as a percentage of the weight lost from the initial weight, and the oxygen and carbon dioxide concentrations were measured using an infrared sensor through a needle in the film.…”

“…A sensory test for overall quality and off-odor was conducted by five skilled panels. The overall quality grade was assumed as follows: 5 points for the best condition before storage, 3 points for maintaining a marketable value, and 1 point for a condition needing disposal [22]. The off-odor was defined as follows: 1 point for not being able to smell the odor and 5 points for a very strong odor.…”

Managing the Product Quality of Vegetable Crops under Abiotic Stress

“…Grafting as a method to mitigate the impacts of abiotic stress in vegetables was elucidated by a research paper by Ellenberger et al [3] and in a review by Devi et al [11]. Elevated CO 2 levels were either used as pre-harvest conditions in combination with different nitrogen forms [5] or as post-harvest treatment combined with different methods of packaging [12].…”

“…Leafy vegetables and herbs-such as arugula [5], purslane [6] and basil [7]-were used in three experiments and were cultivated in growth cabinets [5,6] or in greenhouses [7]. The bulbs of onions were harvested from plants in a field trial [10], and the asparagus spears for a storage experiment were obtained from local farmers [12].…”

“…The impacts of post-harvest conditions on the quality of vegetables are represented as well. Wang et al [12] combined elevated CO 2 pre-treatments and different packaging methods in order to assess the effects on different quality characteristics of green asparagus in cold storage. The authors showed that continuous application of elevated CO 2 reduced the decay of the asparagus spears to the greatest extent by inhibiting the microbial development.…”