عنوان

Evaluation of quality of frozen lowbush blueberries by determination of physical, chemical and sensory characteristics

Number

TLpq304356345

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

Evaluation of quality of frozen lowbush blueberries by determination of physical, chemical and sensory characteristics

General Material Designation

[Thesis]

First Statement of Responsibility

H. Zhang

Subsequent Statement of Responsibility

A. Bushway

Name of Publisher, Distributor, etc.

The University of Maine

Date of Publication, Distribution, etc.

1997

Specific Material Designation and Extent of Item

127

Dissertation or thesis details and type of degree

Ph.D.

Body granting the degree

The University of Maine

Text preceding or following the note

1997

Text of Note

Part 1: Factors affecting physical and chemical characteristics of frozen lowbush blueberries. The objective of this research was to evaluate the effects of processing steps on the quality of frozen lowbush blueberries. The results have shown that harvest time significantly (P usd\leusd 0.05) affected both physical and chemical variables. Later harvested berries tended to have higher sugar migration and ACN leakage. Machine harvested berries were higher in sugar migration (16.7%), ACN leakage (18.9%) and damaged berries (19.9%) than hand-harvested fruit. Frozen berries subjected to compression and abrasion had higher (P usd\leusd 0.05) sugar migration, ACN leakage and damaged berries than non-abused fruit. Compression, abrasion and drop abuse of fresh berries seemed not to affect sugar migration, ACN leakage and Hunter values, but berries undergoing drop during processing were significantly (P usd\leusd 0.05) softer than non-abused, abrasion and compressed fruit. Berries with the lowest post-freezing mass average temperature had significantly less (P usd\leusd 0.05) sugar migration, but higher ACN leakage than semi-frozen berries. Delaying processing for 48 hrs produced softer berries with higher sugar migration and ACN leakage than those held 24 hrs prior to processing. Washed fruit was significantly (P usd\leusd 0.05) softer than non-washed fruit. Part 2: Reduction in anthocyanin leakage of individually quick frozen (IQF) lowbush blueberries in blueberry muffins by gum coating. The objective of this research was to develop a method to prevent bleeding of IQF blueberries in muffins. Rerun berries had a significantly (P usd\leusd 0.05) higher drip loss and anthocyanin leakage in buffer, and demonstrated higher bleeding area in muffins than first-run berries. Batter with coated berries had significantly (P usd\leusd 0.05) higher L values than that with uncoated berries. Batter with uncoated rerun berries had significantly (P usd\leusd 0.05) higher hue angle and negative a value, and lower L, and b value and chroma than that with coated first-run and coated rerun berries. Gum coating significantly reduced anthocyanin leakage into batter during mixing. Muffins with first-run and rerun berries coated with CMC had the lowest sensory bleeding scores of 1.5 and 1.3, respectively. Coating rerun IQF blueberries with gum arabic, guar, CMC and gellan gums reduced berry bleeding in muffins. CMC was the most promising coating material because it forms a firm film surrounding the berries.

anthocyanin

Biological sciences

bleeding

Food science

gum coating

muffins

A. Bushway

H. Zhang

Electronic name

p

[Thesis]

276903

a

Y