Research On Process Of Hard Cheese And The Ripening Characteirstic Of Skim Milk Cheese

This article aims to study the process of hard cheese and the ripening characteristic ofskim milk cheeses, provide some theoretical reference for process improvement andextension of the shelf life of hard cheese. Experiment with hard cheese technology, based onthe low-fat hard cheese process optimization improvements. Through this process preparedskim cheese and whole milk cheese (fat content of about45%) and stored it at4℃0-35Angel vacuum packaging under its maturity. Studied the physicochemical properties of theirmature period (including moisture, ash, acidity, fat, protein, soluble protein, texturalproperties, amino acid content) and cheese flavor compounds, the results showed that:By single factor experiments and sensory assessment of the amount of leavening agentadded, the amount of calcium chloride added, pre-acidification time, amount of rennetadded, curd temperature, holding temperature and holding stir stirring time were screenedand found the amount of leavening agent added, holding stirring time, the stirringtemperature and thermal amount of calcium chloride have a significant effect on the yield andquality of cheese. Response surface methodology for process optimization of low-fat cheese,optimal parameters obtained as follows: the amount of leavening agent added0.8%heatstirring time40min, heat stirring temperature42℃, the amount of calcium chloride added0.04%.Under vacuum packaging storage at4℃, with the extension of maturity of time,moisture, ash and fat content of skim and whole milk cheese gradually decreased, acidity andelevated protein in a downward trend after the first, and pH4.6-SN and12%TCA-SN ismanifested in a gradual upward trend. Textural characteristics of the two cheese ripeningtime of change as you grow more significant.Moisture, protein content, total amino acids andtextural aspects, better than full-fat cheese, skim milk cheese; while changes in acidity,protein degradation, the full-fat cheese than skim cheese.8essential amino acids in full-fat cheese and skim more abundant around38%.In the8essential amino acids of skim cheese Val, Ile, Met, Thr, Lys, Phe, Leu were significantlyhigher than full-fat cheese.Glu, Cys, Leu, Pro were significantly in skim cheeses;In additionto these four, Asp, Val, Tyr, Lys, Arg were also showed significant changes in full-fat cheeses. These amino acids have a great influence in cheeses’ flavor especially in full-fatcheese.Experiments using solid phase micro extraction (SPME) of volatile components duringripening cheese for extraction. In the extraction of the SPME fiber head and the extractiontemperature screening results:75μm CAR/PDMS fiber head out of the total number ofpeaks and the highest peak in the area when the hatch60℃.By headspace solid phase micro extraction GC-MS technique (HS-SPME-GC/MS)flavor detection skim and whole milk cheese ripening cheese, the results showed that:27kinds of Chinese Communist Party in skim cheese volatile compounds detected, its Sortrelative content is: carboxylic acids> alcohols> ketones> aldehydes> esters> hydrocarbonsand other compounds; whole cheese in32kinds of substances were detected, which is sort ofrelative content: carboxylic acids> alcohols> ketones> esters> aldehydes> hydrocarbonsand other compounds.Carboxylic acids and alcohols, cheese and whole milk for skim cheese flavorcontribution is large. Wherein: acetic acid, propionic acid, hexanoic acid, hexanol, benzylalcohol,2-nonyl ketone, butyl butyrate, acetaldehyde, nonyl aldehyde constitute the mainbody of the skim milk cheese flavor; acetic acid, caproic acid, butyric acid, caproic alcohol,benzyl methanol,2-heptanone,2-nonyl ketone, propyl hexanoate, nonyl aldehyde bodyconstituting whole cheese flavor.