dehydrated & human-grade pet food

*Drying or “dehydrating” food is a method of natural food preservation that removes enough moisture from the food so bacteria, yeast and molds cannot grow.

01 highest nutrition at low temperature drying

The effect of vacuum packaging on nutritional compounds and quality parameters of dried galega kale, using three air-drying temperatures, was analysed during twenty weeks of storage. The higher drying temperature (70°C) resulted in lower concentrations of all nutritional parameters, whereas the lowest tested temperature (40°C) yielded higher values. Packaging using vacuum did not add value to the dried product, since similar or better results were obtained for most nutritional parameters using the samples packaged at normal atmosphere. All nutritional compounds decreased during the storage period, with vitamin C being the most affected. In relation to the colour properties, similar results were obtained for both packages at all drying temperatures, allowing concluding that packaging without the need of vacuum provided the attainment of a dried product with a visual aspect analogous to the sample packaged using vacuum.

link to article: Ana C. Araújo, Sara M. Oliveira, Inês N. Ramos, Teresa R. S. Brandão, Maria J. Monteiro, Cristina L. M. Silva, "Evaluation of Drying and Storage Conditions on Nutritional and Sensory Properties of Dried Galega Kale (Brassica oleracea L. var. Acephala)", Journal of Food Quality, vol. 2017, Article ID 9393482, 9 pages, 2017.

02 heat processing destroys vitamin A & E

The oxidative changes that accompany the beginning and development of rancidity in unsaturated animal fats tend to destroy vitamins A and E. It is generally accepted that vitamin A as found in butter fat and cod liver oil is easily destroyed. Heating and aerating these fats for a short time or exposing them to air at room temperature for a longer period usually deprives them of every trace of vitamin A. During such treatment the fats absorb oxygen and a long series of partial oxidation products is recognized as accompanying the more or less undefined condition of rancidity so developed. However, vegetable oils have the opposite effect. Since vegetable oils, especially wheat germ oil, although having as high or higher iodine numbers, contain more hydroxy compounds than lard, cod liver oil, butter and other animal fats, they delay autoxidation in fats and thereby prevent accompanying destruction of vitamins A and E.

Link to article: Mattill h. The oxidative destruction of vitamins a and e: and the protective action of certain vegetable oils. Jama.1927;89(18):1505–1508.

03 heating process increases cancer risk

When foods are being processed or cooked at high temperature, chemical reaction between amino acids and reducing sugars leads to the formation of Maillard reaction products (MRPs). Depending on the way the food is being processed toxic MRPs can be produced. For example, acrylamide has been classified as a probable carcinogen, A carcinogen is a substance, organism or agent capable of causing cancer by the International Agency for Research on Cancer

Link to article on Maillard reaction: Tamanna, Nahid; Mahmood, Niaz (2015). Food Processing and Maillard Reaction Products: Effect on Human Health and Nutrition. International Journal of Food Science, 2015(), 1–6.

Link to article on acrylamide cancer risk: Cancer IAfRo, IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Overall Evaluations of Carcinogenicity: An Updating of IARC Monographs, vol. 1–42, World Health Organization, 1987.

04 human-grade more digestible than kibble & fresh food

Human-grade (HG) pet foods are commercially available, but they have not been well studied. Our objective was to determine the apparent total tract digestibility (ATTD) of HG pet foods and evaluate their effects on fecal characteristics, microbiota, and metabolites, serum metabolites, and hematology of dogs. As expected, the HG foods had an extremely high digestibility that was higher than that of extruded and fresh diets, without any differences observed in regard to fecal characteristics (pH or score) or metabolites.

Link to article: Sungho Do, Thunyaporn Phungviwatnikul, Maria R C de Godoy, Kelly S Swanson, Nutrient digestibility and fecal characteristics, microbiota, and metabolites in dogs fed human-grade foods, Journal of Animal Science, Volume 99, Issue 2, February 2021, skab028.

05 minimum/no heat treatment highest nutrient digestibility 

the objective of this study was to determine the apparent total-tract macronutrient digestibility (ATTD); fecal characteristics, metabolites, and microbiota; serum chemistry metabolites; urinalysis; and voluntary physical activity levels of adult dogs fed commercial diets differing in processing type. The diets included: 1) extruded dry kibble (EXT) diet; 2) high-moisture roasted refrigerated (RR) diet; 3) high-moisture grain-free roasted refrigerated (GFRR) diet; and 4) raw (RAW) diet. In conclusion, the lightly cooked and raw diets tested were highly palatable, highly digestible, reduced blood triglycerides, maintained fecal quality and serum chemistry, and modified the fecal microbial community of healthy adult dogs.

Link to article: Algya KM, Cross TL, Leuck KN, Kastner ME, Baba T, Lye L, de Godoy MRC, Swanson KS. Apparent total-tract macronutrient digestibility, serum chemistry, urinalysis, and fecal characteristics, metabolites and microbiota of adult dogs fed extruded, mildly cooked, and raw diets1. J Anim Sci. 2018 Sep 7;96(9):3670-3683.

06 extrusion (kibble) harms vitamin retention in pet food

The extrusion process of pet food consists in the steam conditioning of a mixture of ingredients that is compressed and forced through a die while being heated at the same time. The kibbles are cut down into regular sizes by rotating knives at the die’s exit. Additionally, due to a pressure drop at the die’s exit, the moisture evaporates quickly and the extrudate expands. The method has however adverse effects on vitamins. In addition to being sensitive to heat, light, oxygen, moisture and mineral content , vitamins are exposed to high pressure and shear conditions during extrusion, which might lead to important losses. Vitamins are a group of complex organic compounds required in small amounts to cover metabolic needs. Since commercially prepared pet food is most commonly the main source of nutrients for dogs and cats, vitamin loss is a serious issue as deficiencies can cause severe illnesses or even death of the animal. The present literature review has highlighted that the fat-soluble vitamins A, D, E, and K, as well as vitamin C and folic acid were the least stable vitamins during extrusion. The most detrimental parameter for those were temperatures above 100 ◦C and in the case of vitamin E and C, increasing moisture was as detrimental as increasing the temperature.

link to article: Riaz, Mian N.; Asif, Muhammad; Ali, Rashida (2009). Stability of Vitamins during Extrusion. Critical Reviews in Food Science and Nutrition, 49(4), 361–368.