Emilia Bernaś

Effect of microwave blanching on the quality of frozen Agaricus bisporus.

The aim of this work was to determine the effect of microwave blanching on the levels of selected quality parameters in frozen Agaricus bisporus. Before freezing, mushrooms underwent one of the following treatments: blanching in water; blanching in a solution of sodium metabisulphite and citric acid; microwaving for 5 min; and combined blanching (first in water, then in a microwave oven). Products were freeze stored for 8 months at –25 ℃. Frozen storage resulted in decreased levels of vitamin B1, total polyphenols and antioxidant activity of 10–49%, as well as an increase in polyphenol oxidase activity compared with products immediately after freezing. The values for most colour parameters and whiteness intensity decreased, while cream, yellow, brown and grey saturation increased. There was a considerable deterioration in sensory quality, particularly colour. Microwave-blanched products had significantly higher dry matter, ash, vitamin B1 and B2 content than the remaining products as well as half the polyphenol oxidase activity. Total polyphenols and antioxidant activity were highest in the product blanched in the sodium metabisulphite solution, followed by the microwave-blanched product. Compared with the product blanched using sodium metabisulphite, microwave-blanched mushrooms showed slightly greater darkening but were superior in flavour and aroma.

Comparison of Amino Acid Content in Canned Pleurotus Ostreatus and Agaricus Bisporus Mushrooms

Comparison of Amino Acid Content in Canned Pleurotus Ostreatus and Agaricus Bisporus Mushrooms The work compares the levels of amino acids in canned Pleurotus ostreatus and Agaricus bisporus mushrooms. Compared with A. bisporus, P. ostreatus contained significantly lower levels of ash, total nitrogen and protein nitrogen (by 17-40%), but 12% more total carbohydrates. Protein nitrogen constituted 87% of the total nitrogen in A. bisporus and 72% in P. ostreatus. The conversion factor from total nitrogen to protein was 3.45 in A. bisporus, 15% lower than in P. ostreatus. In both species, glutamine was the most abundant endogenous amino acid while leucine was the most abundant exogenous amino acid. The least abundant endogenous and exogenous amino acids were respectively glycine, and methionine and cysteine. When the results were expressed in terms of per 100 g of fresh matter, P. ostreatus contained significantly higher levels of arginine, tyrosine and valine than A. bisporus (by 14-21%), but lower levels of alanine, asparagine, glutamine, glycine, cysteine and histidine (by 5-38%). In terms of per 100 g of protein, P. ostreatus contained significantly higher levels of alanine, arginine, glycine, isoleucine, leucine, phenylalanine, threonine, tyrosine and valine (by 9-40%) than A. bisporus, but lower levels of asparagine, glutamine, proline and cysteine (by 5-37%). Compared with the FAO/WHO reference protein patterns, no limiting amino acids were found in either species. The EAA (Essential Amino Acid) index values for canned P. ostreatus were 11% higher than for canned A. bisporus. Porówananie Zawartości Aminokwasów w Sterylizowanych Owocnikach Boczniaka Ostrygowatego i Pieczarki Dwuzarodnikwej W pracy porównano zawartość aminokwasów w sterylizowanych owocnikach pieczarki dwuzarodnikowej (Agaricus bisporus (Lange) Sing.) i boczniaka ostrygowatego (Pleurotus ostreatus (Jacq.: Fr.) Kumm.)). Sterylizowane boczniaki, w porównaniu do pieczarek, charakteryzowały się istotnie mniejszym poziomem popiołu, azotu ogółem i azotu białkowego o 17-40%, natomiast wyższym węglowodanów ogółem o 12%. Azot białkowy stanowił 87% azotu ogółem w przypadku konserw z pieczarek i 72% z boczniaków. Współczynnik przeliczeniowy azotu ogółem na białko w przypadku pieczarek wynosił 3,45 i przyjmował wartość niższą o 15% niż u boczniaka. W obu gatunkach grzybów wśród aminokwasów endogennych w największej ilości występowała glutamina, zaś spośród aminokwasów egzogennych leucyna. W najmniejszej ilości oznaczono glicynę oraz cysteinę i metioninę. Przy wyrażaniu wyników w 100 g świeżej masy sterylizowane boczniaki, w porównaniu do pieczarek, charakteryzowały się istotnie większym poziomem argininy, tyrozyny i waliny o 14-21%, natomiast mniejszym alaniny, asparaginy, glutaminy, glicyny, cysteiny i histydyny o 5-38%. W przeliczeniu na 100 g białka w sterylizowanych owocnikach boczniaka wykazano istotnie więcej alaniny, argininy, glicyny, izoleucyny, leucyny, fenyloalaniny, treoniny, tyrozyny i waliny o 9-40%, natomiast mniej asparaginy, glutaminy, proliny, cysteiny o 5-37% niż w produktach z pieczarki. W porównaniu do wzorców białka FAO/WHO w analizowanych grzybach nie stwierdzono żadnych aminokwasów ograniczających. Indeks EAA był wyższy o 11% w sterylizowanym boczniaku niż w pieczarce

Qualitative comparison of blackcurrant and blackcurrant—whey beverages

This study provides a qualitative comparison of blackcurrant and blackcurrant—whey beverages over a 12-month storage period. The amount of extract in the beverages was established as 12%, of which 25% was blackcurrant concentrate. Acid whey was used for the production of blackcurrant—whey beverages. In comparison to blackcurrant—whey beverages, blackcurrant beverages contained significantly more glucose, fructose, sucrose, polyphenols and vitamins C and B1. They also had a higher level of antioxidant activity against ABTS•+ and DPPH, with the difference ranging from 2% to 46%. On the other hand, blackcurrant—whey beverages contained more ash, proteins and vitamin B2 and the presence of lactose was detected. They were also characterized by higher color parameter values evaluated according to the CIE system. A general sensory evaluation awarded blackcurrant beverages with 0.5—1.3 more points than blackcurrant—whey beverages. A descriptive flavor analysis found that blackcurrant taste dominated in both types of beverages; however, in blackcurrant—whey beverages, the taste and smell of whey were also discernible. Changes in the quality of the beverages were observed during the storage period, notably a decrease in their antioxidant properties.