Causes and Remedies for Green Discoloration of Processed Garlic Puree: Effects of Storage Conditions on Ingredient Bulbs

Abstract

Storage experiments on garlic (Allium sativum L.) bulbs were conducted to elucidate the causes and prevention of green discoloration (greening) of garlic puree, a severe problem in garlic processing. Greening of the pureed bulbs increased with the accumulation of S-(E-1-propenyl)-l-cysteine sulfoxide (isoalliin), which is metabolized from N-(γ-glutamyl)-S-(E-1-propenyl)-l-cysteine (Glu-PEC) during cold storage (3℃). Greening was reduced by warm storage ( > 25℃) of the cold pre-stored bulbs, with an accompanying decrease in isoalliin. Accumulated isoalliin in the garlic bulbs during cold storage was converted to 5-methyl thiomorpholine-3-carboxylic acid sulfoxide (cycloalliin) with warm storage ( > 25℃). The relationship between warm storage conditions (temperature, duration) and decreases in isoalliin content were presumed to be applicable to a first order-Arrhenius equation. Two-week storage of the ingredient garlic bulbs at 40℃, after cold pre-storage at 3℃ for 12 weeks, sufficiently reduced greening of the processed puree to maintain the commercial quality of the bulbs.

High pressure processing of garlic paste: effect on the quality attributes

“…But, with high pressure processing, a* value shifted more towards a greenish region. Although greening mechanism as a result of processing has not been elucidated adequately, studies suggest that greening of garlic products results from the accumulation of S ‐( E ‐1‐propenyl)‐l‐cysteine sulfoxide (Yamazaki et al ., ). However, it is evident from the present study that high pressure processing was more effective than thermal processing in retaining yellowness of the fresh sample ( b* value) with over 72.44% being retained in garlic paste processed at 600 MPa compared with a figure of 44.65% and 65% for 200 and 400 MPa pressure‐treated samples, respectively.…”

Isolation and Identification of Causal Constituents of Green Discoloration in Garlic Puree

“…1). We have reported effective methods for decreasing isoalliin in garlic bulbs (Yamazaki et al, 2012).…”

“…Characterization of the green discoloration and development of the assay method The garlic bulbs were stored at 3℃ for 12 weeks prior to experiments, as cold storage of garlic bulbs is known to cause accumulation of isoalliin in garlic, and to enhance greening of the processed purees (Lukes, 1986;Bai et al, 2005;Yamazaki et al, 2012).…”

Garlic greening: Pigments biosynthesis and control strategies

“…This mechanism could be exploited also in the case of refrigerated storage. Indeed, if cold storage conditions (below 0°C) are not available, cloves can be stored at refrigerated conditions and then subjected to warm storage (35-40°C for 2 weeks) to allow the conversion of isoalliin to cycloalliin and produce garlic bulbs without noticeable changes in color (Yamazaki et al, 2012).…”