New Methods for the Evaluation of Barley and Malt

Abstract

The frequent appearance on the French market of new barley varieties, especially two-row and six-row winter types, has caused some delays in adapting malting and brewing procedures. Malting studies with several quantities (10 and 250 g; 2 and 300 kg) of barley have been conducted, and evaluations were made of malt at various malting times. Some of these malts were tested by microbrewing (7 L) and by pilot scale (2,000 L) brewing. The methods of Aalbers/Greif (methylene blue) and of Carlsberg (Calcofluor) were used to measure the modification and the homogeneity of malts. The InfraAlyzer was used to measure modification, but this method does not measure homogeneity. The TEPRAL mashing system was also used. Its advantage is that in addition to the determination of extract, other parameters of industrial importance are measured. The close relationship between filtrability of the TEPRAL mash and filtrability of beer is discussed. The application of these new analytical methods allows better evaluation of barleys and of malts prepared at micro, pilot, and industrial scales.

Tandem Mass Spectrometry for Sequencing Proanthocyanidins

“…The difficulty of extracting and purifying PAs, together with their instability, structural complexity, and limited quantities present in hops, makes this source particularly relevant for implementing protocols to structurally characterize them. The estimated amount of PAs in hop ranges from 0.5 to 5% on a dry weight basis, depending on variety and geographic origin. ,

1 Flavanol Units of PAs in Hops Cones a a n , degree of polymerization; A−F, ring labels.

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Proanthocyanidins in Hops

“…The major hop proanthocyanidins, catechin ( Stevens et al , 2002 ), epicatechin ( Stevens et al , 2002 ), ( McMurrough, 1981 ;Moll et al , 1984 ), catechin-(4␣; 8)-catechin (procyanidin B3) ( McMurrough, 1981 ;Moll et al , 1984 ), catechin-(4 ␣; 8)-epicatechin (procyanidin B4) ( McMurrough, 1981 ;Moll et al, 1984 ) and epicatechin-(4␤; 8)-catechin-(4 ␣; 8)-catechin ( Stevens et al , 2002 ), were identifi ed early on by several research groups using NMR, HPLC, MS and chemical degradation. But it was diffi cult to elucidate the structures of minor hop proanthocyanidins by NMR because of both the low amounts available and the multiplicity and broadening associated with rotational and conformational isomerism that often complicates the interpretation of the spectra.…”