Rehuna käytettyjen sivuvirtojen säilöntä vakumoimalla : Mäski ja perunapulppa

Abstract

Työn tarkoitus oli selvittää, miten vakumointimenetelmä soveltuu mäskin ja perunapulpan säilöntään ja miten säilöntäaika vaikuttaa laatutekijöi-hin, taustalla oli HAMK:n ArvoBi-hanke. Tavoitteena oli selvittää, voitai-siinko perunapulpan ja mäskin säilyvyyttä parantaa vakumoinnin ja hap-polisän avulla. Tutkimus suoritettiin HAMK:n bio- ja elintarviketekniikan laboratorioissa. Tutkittavat biomassat saatiin yhteistyökumppaneilta.

Tutkimuksessa selvitettiin perunapulpan säilyvyyttä 21 vuorokauden ajan ja mäskin 49 vuorokauden ajan. Kaikista näytteistä mitattiin kuiva-ainepitoisuus, pH, painonmuutos ja anaerobisten sulfiittia pelkistävät bak-teerit. Mäskin näytteistä mitattiin myös proteiinipitoisuuden muutokset.

The purpose of this thesis was to research how vacuum packaging can guarantee the long-lasting preservation of beer mash and potato pulp. The underlying research was part of the ArvoBio project in HAMK. The aim was to examine if the preservation of beer mash and potato pulp could be more effective by using vacuum and acid addition. The study was carried out in the HAMK laboratory of biotechnology and food engi-neering; the biomass specimens were received from the cooperation partners.

The study looked at how well the potato pulp preserved for 21 days and the beer mash for 49 days. Each sample was measured of their total sol-ids, pH, change in weight and anaerobic sulphate-reducing microorgan-isms; from the beer mash protein was also measured.

In both potato pulp and beer mash the amount of sulphate–reducing clostrides did not increase in the samples except the potato pulp’s in ad-ditional acid sample. The pH decreased in both to desired level (pH 4) in the vacuum preservation; in the potato pulps open preservation it did not hit pH 4 but went between pH 4.30‒6.56. Changes in potato pulps total solids concentration were around 1 % except open preservation which change was over 3 %; in the beers, samples total solids decreased, except in fresh vacuum additional acid preservation increase 8 %. In the sam-ples, the fresh beer mash had most protein in begin; the protein re-mained well in the fresh vacuum.

The study can considered as pilot study. Both products benefited from vacuuming; the vacuuming had lover the pH and no molds were generat-ed. In beer mash can be considered drop off the addition of acid; beer mash will go naturally under hoped pH.