Deteriorarea mierii prin incalzire

Pornind de la preocuparea pentru miere, dar mai ales de la un comment al Simonei, am luat la puricat si Wikipedia, pe subiectul acesta. Pe Wiki, si surorile ei, le puric des, pe subiecte de toate felurile, care de care mai bizare, pe tema asta inca nu cercetasem ...


Sunt foarte multe lucruri interesante de aflat, in link-ul indicat, eu am retinut un paragraf care ma interesa in mod special

Excessive heat can have detrimental effects on the nutritional value of honey.[63][64] Heating up to 37 °C (98.6 °F) causes loss of nearly 200 components, some of which are antibacterial. Heating up to 40 °C (104 °F) destroys invertase, an important enzyme. At 50 °C (122 °F), the honey sugars caramelize. Generally, any large temperature fluctuation causes decay.[65]

Deci nu, nu spune ca ar fi toxica, doar ca

However, excessive heat exposure also results in product deterioration, as it increases the level of hydroxymethylfurfural (HMF) and reduces enzyme (e.g. diastase) activity.

Dupa ce am citit concentrata la maxim (ca nu sunt deloc prietena cu chimia), wiki mi-a concluzionat foaaarte frumos ca

A major metabolite in humans is 5-hydroxymethyl-2-furoic acid (HMFA), which is excreted in urine. HMF can also be metabolized to 5-sulfoxymethylfurfural (SMF), which is highly reactive and can form adducts with DNA or proteins. In vitro tests and studies on rats suggest potential toxicity and carcinogenicity of HMF.[14] In humans, no correlation between intakes of HMF and disease has yet been demonstrated.[citation needed]

mai detaliat spune ca

HMF is practically not present in fresh food, but it is naturally generated in sugar-containing food during heat-treatments like drying or cooking. Along with many other flavor- and colour-related substances, HMF is formed in the Maillard reaction as well as during caramelization. In these foods it is also slowly generated during storage. Acid conditions favour generation of HMF.[8]
HMF can be found in low amounts in honey, fruit-juices and UHT-milk. Here as well as in vinegars, jams, alcoholic products or biscuits HMF can be used as an indicator for excess heat-treatment. For instance, fresh honey only has low amounts of HMF—less than 15 mg/kg—depending on pH-value and temperature and age,[9] and the codex alimentarius standard requires that honey have less than 40 mg/kg HMf to guarantee that the honey has not undergone heating during processing, except for tropical honeys which must be below 80 mg/kg.
Higher quantities of HMF are found naturally in coffee and dried fruit. Several types of roasted coffee contained between 300 – 2900 mg/kg HMF.[10] Dried plums were found to contain up to 2200 mg/kg HMF. In dark beer 13.3 mg/kg were found,[11] bakery-products contained between 4.1 – 151 mg/kg HMF.[12]
HMF can form in high-fructose corn syrup (HFCS), levels around 20 mg/kg HMF were found, increasing during storage or heating.[9] This is a problem for American beekeepers because they use HFCS as a source of sugar when there are not enough nectar sources to feedhoneybees, and HMF is toxic to them. Adding bases such as soda ash or potash to neutralize the HFCS slows down the formation of HMF.[9]
Depending on production-technology and storage, levels in food vary considerably. To evaluate the contribution of a food to HMF intake, its consumption-pattern has to be considered. Coffee is the food that has a very high relevance in terms of levels of HMF and quantities consumed.
HMF is a natural component in heated food but usually present in low concentrations. The daily intake of HMF may underlie high variations due to individual consumption-patterns. It has been estimated that in a western diet, in the order of magnitude of 5 – 10 mg of HMF are ingested per day from food.[8]
In former times, HMF was used in food for flavoring purposes, but in Europe this practice now is suspended. HMF is also found in cigarette smoke.[13]

Deci analizand pe Wikipedia, ajung la aceeasi concluzie pe care o aveam si initial :) nu cred ca mierea incalzita peste 70 de grade este mai toxica decat zaharul rafinat sau alte alimente pe care le consumam frecvent, insa mi se pare o mare pierdere sa o distrugem incalzind-o.

Aveti grija de unde o cumparati, nu va stresati daca este zaharisita, preferati-o asa decat fluida, transparenta si stralucind in vre-un soare orbitor ... aceea nu mai e chiar cum trebuie. Si prin exemplele date anterior ma refer doar la mierea deteriorata prin tratare termica si conservare in conditii inadecvate, nici nu am ajuns pe directia cu producatorii, mai mari sau mai mici, care ar pune in ea, cu buna stiinta, diverse porcarii, care ar face dintr-un produs inutil (exemplele anterioare, cand este doar indulcitor, care si-a pierdut proprietati benefice), unul destul de daunator.

Am primit de la Mona (multumesc pt preocupare!), zilele trecute, ceva ce mi-a dat foarte mult de gandit.

Este vorba despre un tabel (Mona, te rog mult sa-mi indici si sursa!) ce contine datele unor analize realizate in laboratorul Institutului de Cercetare-Dezvoltare pt Apicultura SA din Bucuresti. Analize facute pe cateva sortimente de miere de salcam, ce se gasesc spre comercializare in cateva hiper-market-uri din Bucuresti.

Analiza pe surse de miere

Pe mine ma socheaza, pe langa glucuza industriala continuta de majoritatea sortimentelor analizate, faptul ca desi acele recipiente ar fi trebuit sa contina miere de salcam (care se vinde mai scump decat celelalte sortimente), ele contin procente foarte mari de miere din alte plante.
Se stie ca lumea prefera mierea de salcam, pentru ca aceasta isi pastreaza fluiditatea mai mult timp. Se profita de aceasta informatie pt a se comercializa alte tipuri de miere, care sunt fluidizate si transparentizate, nu se stie prin ce metode sau adaosuri, care tipuri sunt vandute pe post de miere de salcam.
As fi fost curioasa sa stiu si ce alte componente mai contineau acele mostre, in afara de miere :)

Chiar nu inteleg de ce se face treaba asta, pe mine ma infurie foarte tare ideea de a fi pacalita, de aceea incerc sa-mi produc singura cat de multe alimente sau sa le iau din surse sigure, care sa nu ma rupa chiar complet la bani.
De aceea prefer sa ajut la constientizarea acestor lucruri, sunt informatii care trebuiesc impartasite.

Gata! Ma duc la supravegheat copiii prin curte.

Au venit de jos, de la bunici, foarte entuziasmati ca nu s-au uitat la desene (i-am cam bumbacit ca au crescut iar doza zilnica) ci s-au uitat la niste oameni care s-au baltocit :) 

Eu eram !!! Mi s-a explicat promt ca au facut si ei ca mormolocii pe covor, uitandu-se la niste oameni care au inotat "pe culoare" :)